LIBRARY OF CONGRESS. 



BoynesTiG sgienge. 



A BOOK FOR USE IN SCHOOLS AND 
FOR GENERAL READING. 

(SECOND AND I^E^ISED EDIXION,) 



BY 



JAMES E. TALMAGE, 

(d. S. D., Ph. D., F. R. M. S.) 



" Till, by experience taught the mind shall learn 
That, not to know at large of things remote 
From use, obscure and subtle, but to know- 
That which before us lies in daily life, 
Is the prime wisdom."— Milton. 



jrs^sr3 X 



PUBLISHED BY 

GEORGE Q. CANNON & SONS CO., 

SALT LAKE CITY, UTAH. 

1892. 




COPYllIGHTED 1803 

— BY — 

J. E. TALMAGE. 



DEDICATORY. 

TO 

KARL G. MAESER, D. L. D., 

To whom the author owes so much, this 
unpretentious volume is respect- 
fully and affectionately 
inscribed. 



FROM PREFACE TO FIRST EDITION. 



The author has endeavored to bring together, in a 
simple manner, such topics as have a direct bearing 
upon the science of domestic operations. His object 
has been to direct attention to daily household affairs, — 
affairs indeed, which to many are too common to be 
deemed worthy of earnest thought. The kitchen and 
the pantry may be made a laboratory for the elucidation 
of many important facts of science ; and as interest is 
aroused in the necessary labors of the household, much 
of the unwelcome air of drudgery will vanish from 
such work. As it is plain that the duration of our 
mortal existence permits the exploration of but a small 
fraction of the domain of knowledge, careful judgment 
should be exercised in the selection of subjects of 
study ; the practical and utilitarian aspect of modern 
systems of education testifies to the wide recognition 
this fact has received among the people in general. 

In this book, no effort has been made to secure an 
unduly elaborate or an exhaustive treatment ; a large 
work would be poorly adapted for class use, and much 
detail might discourage the general reader in his 
study. Liberal reference has been made to the works 
of recognized authorities on the subjects treated ; in 
such cases, acknowledgment has been made in the body 
of the work. A few passages are reprints of articles 
that have appeared over the author's signature in local 
periodicals. 



PREFACE TO SECOND EDITION. 



" Domestic Science " having been adopted by the 
Territorial Convention of School Officers, as a text 
book for the District Schools of Utah, the publication 
of a second edition is rendered necessary. The author 
has endeavored to improve the little work by correcting 
a few typographical and other errors of the first issue, 
and by adding a brief set of review propositions at the 
end of each chapter. These with the addition of a 
few statements, a re -arrangement of some paragraphs, 
and some omissions, constitute the principal changes, 
the main plan of the work remaining unaltered. The 
publishers have had prepared a new series of illus- 
trative cuts, which will doubtless be appreciated. 

For the measurement and calculations relative to 
the Tabernacle in Salt Lake City, the author is 
indebted in this, as in the first edition, to Architect 
Don C. Young. 

It is hoped that the book in its present form will 
prove of some value to the writer's fellow -laborers, — 
teachers and students. 

J. E. T. 
Salt Lake City, Utah, 
Dec, 1892. 



ANALYSIS OF CONTENTS, 



P^'jPlI^T I. 

AIR AND VENTILATION, WITH CHAPTERS ON HEATING 
AND LIGHTING. 



. Chapter 1. 

Page. 

Some physical properties or air; impenetrability of air; 

air pressure; weight etc; expansion of air by heat; 

air-pump, and experiments with same - 11 

Chapter 2. 

Simple instruments utilizing atmospheric pressure; 
simple barometer; siphon barometer; wheel baro- 
meter; aneroid barometer; storm -glass; syringe; 
lifting pump; force pump pipette; siphon - 24 

Chapter 3. 

Composition of the Atmosphere; diffusion of gases; 

nitrogen; oxygen; carbon-dioxide; vapor of water 38 

Chapter 4, 

Permanency of the atmosphere; plants as agents of 
atmospheric purification; fungi and chlorophyle- 
bearing plants; mollusks and corals as removers of 
carbon dioxide; mutual dependence of animals and 
plants .-..---. 51 

Chapter 5. 
The air of rooms; contamination from presence of human 
beings; proximity of stables, etc. ; rate of contamina- 
tion; effect of lights and fires; cellars beneath dwell- 
ings -.-...._ 60 

Chapter 6. 
Ill effects of impure air; human respiration; foul air 
productive of scrofula; tuberculosis; tonsilitis; 
dysentery effect of foul air on mental powers; popu- 
lar disregard of need for pure air - - - 71 



IV CONTENTS. 

Chapter 7. 

Page. 
Dust in the air; dust- inhaling occupations; coal miners 
and tin miners; poisonous dust; natural defenses 
against dust; living organisms in dust; household 
dust; carpets, curtains, etc., as dust-traps; wall 
papers, arsenical papers - - - - 81 

Chapter 8. 

Ventilation: opposite currents; mine ventilation; Lyman's 
ventilator; open fire-places as ventilator*; exhaust 
fans; revolving cowls; entering currents through 
windows and transoms . . . _ - 93 

Chapter 9. 
Some properties of heat: expansion of solids by heat; 
force exerted by expanding solids; compensation 
pendulums, gridiron, and mercurial bob; expansion 
of liquids and gases by heat; thermometers, Fahren- 
heit and Celsius scales, dial-face thermometer - 107 

Chapter 10. 
Communication of heat; latent and specific heat, 
conduction in solids; conductors of heat; convection 
in fluids; radiation of heat; latent heat and specific 
heat; latent heat of water; beneficial effects of 
same -......- 120 

Chapter 11, 
Production of heat; fuels and flame; chemical pro- 
ducts of combustion; moisture; carbon-dioxide; 
nature of flame; hollow condition of flame: fuels; 
woods, coal; lignite; cannel coal; bituminous coal, 
semi-bituminous coal; anthracite coal; charcoal; 
coke; coal gas; matches. 130, 

Chapter 12. 

House warming; open fire-place, ancient and modern; 
stoves; double case stove; warmed air; steam warm- 
ing; warm water-heating: low pressure system, high 
pressure system - - - - - - 143 

Chapter 13. 

Light and lighting; light natural and artificial; light in 
dwellings ; candles ; candle flame ; effect of blow-pipe ; 
simple lamp ; Argand lamp; hollow- wick lamp - 154 



CONTENTS. V 

Chapter 14. 

rAGE. 
Lighting continued; common illuminants; illuminating 
oils; flashing point and Are test of oils; coal gas, 
water gas, vapor gas, electric lamps— arc and Incan- 
descent -------- 162 



F^-2PlP2.T II. 

WATEK. 



Chaptek^IS. 
Water— its occurrence;- in minerals; in plants, fresh and 
air dried; absorption of water by plants; force of 
ascending sap; water in animal bodies; in human 
bodies - ------- 173 

Chapter 16. 
Water, some of its uses and properties: as liquid, as 

solid, as vapor; freezing of water; ice crystals - 181 

Chapter 17. 

Sources of water; rain-water; springs; hill-side springs; 
fissure springs; artesian wells; equilibrium of liquids; 
intermittent spring->; water of rivers, of wells - 187 

Chapter 18. 

Water— A solvent for solids; solids in natural waters; 
conditions favoring solution; hardness of water; 
total, permanent and temporary hardness; goitre 
prevalent in regions of hard water occurrence - 197 

Chapter 19. 

AVater— A SOLVENT FOR GASES; atmosphcric gases in water; 
ammonia gas and hydrogen sulphide in water ; carbon 
dioxide in water; soda water; water in the sickroom 206 

CHAPTER 20. 

Organic impurities in water; free ammonia and albumin- 
oid ammonia in water; chlorine in water; ill effects 
of organic contamination of water; suspended matter 
in well water; living organisms in potable water • 212 



Vi CONTENTS. 

Chapter 21. 

Page. 

6IMPLE TESTS FOR PURITY IN POTABLE WATER; Cliemical 

analysis of water; color; clearness; odor; taste; 
tests for chlorine and organic matters; filthy state 
of grave -fed waters - • • • - 221 

Chapter 22. 
PURIEICATION OF WATER; boiling; distillation; filtration; 
domestic filters; alum and tannin in water; waters of 
Marah ; Clark's process for softening water - - 226 

Chapter 23. 

Mineral waters; sulphur waters; carbonated waters; 
calcium waters; chalybeate waters; alum watersf sil- 
iceous waters; saline waters; temperature of spring 
waters; medicinal effect of mineral waters - - 236 

Chapter 24. 
Composition of pure water: electrolysis of water; prepar- 
ation and properties of hydrogen; synthesis and ana- 
lysis of water; oxy -hydrogen fiame - - - 243 



F=jPlP2.T III. 



FOOD AND ITS COOKERY. 



Chapter 25. 

Food, its nature and uses; bodily need of food, classifi- 
cation of foods, — inorganic, organic, and auxiliary; 
advantages of mixed diet; conditions of digestibility; 
object of cooking - . . _ . - 253 

Chapter 26. 

Mineral ingrediknts of food: water, salt, lime, iron, sul- 
phur, and phosphorus, mineral ingredients of food 
within the body - ----- 261 



CONTENTS. Vll 

Chapter 27. 

Page. 

Organic ingredients of food: amyloid group of food sub- 
stances, sources, preparation, and use of starch; 
sugar,— saccliarose and glucose; vegetable gum, dex- 
trin - 269 

Chapter 28. 
Carbonaceous ingredients op food, continued : vegetable 
acids— citric acid, tartaric acid, malic acid, oxalic 
acid; pectin; fats and oils— vegetable fats, animal 
fats, olein, palmitin, stearine - - - -278 

Chapter 29. 

Nitrogenous ingredients of food: albuminoids or pro- 
teids,— albumen, fibrin, gelatin, casein, gluten, pro- 
perties of the albuminoids - - • - 286 
Chapter 30. 

Vegetable foods and their cookery: tubers, bulbs and 
root^, — potatoes, onions, turnips, carrots, parsnips, 
beets, radishes; leaves and leaf -stems,— cabbage, 
salads: fruits; seeds - - - '- - -295 

Chapter 31. 
Vegetable foods, continued: wheat— bread and bread- 
making; yeast, effect of; baking powders; new and 
stale bread; barley; rye; oats; buckwheat; rice « 305 

Chapter 32. 
Animal foods and their cookery: flesh as food; seeth- 
ing; use of water-bath, roasting, broiling or grilling, 
frying; eggs ------- 317 

Chapter 33. 
Animal foods, continued: milk, cream, butter, artificial 

butters, cheese ._..-- 325 

Chapter 34. 
Some auxiliary foods: condiments; vinegar; pickles; 
lemon and lime juices; essential oils as fiavoring 
agents; spices; artificial drinks — tea, coffee, cocoa, 
chocolate - • • - • " • - 331 

Chapter 35. 
Preservation of food stuffs: cause of decay; preserva- 
tion by freezing, by hermetic sealing- canning and 
bottling, by drying, by chemical antiseptics, — salt, 
sugar, alcohol, vinegar, creosote, boric^acid - - 340 



Vlll CONTENTS. 



CLEANSING AGENTS ; AND POISONS AND THEIR ANTIDOTES. 



Chapter 36. 

Page. 

Cleansing agents: water, alkalies, soaps,— hard soaps, soft 

soaps, marine soap, colored soaps, glycerine soaps; 

adulterations of soap; aqua ammonia and other 

cleansing agents - - - - - - 351 

Chapter 37. 

Bleaching: explanation of process: light and air as bleach- 
ing agents; sun bleaching; art of bleaching as prac- 
ticed in Holland; chlorine; bleaching powder; sul- 
phur dioxide --..... 353 

Chapter 38. 

Disinfectants: absorbents, and deodorizers; charcoal and 
lime as absorbents ; chlorine as a disinfectant; chlor- 
ide of lime; sulphur dioxide; carbolic acid; thymol; 
copperas; corrosive sublimate; zinc salts; lead chlor- 
ide; heat; instructions for disinfection - - 364 

Chapter 39. 

Poisons and their antidotes: nature of a poison; general 
treatment in poisoning cases; common poisons and 
antidotes:— mineral acids, organic acids, alkalies, 
antimony, arsenic, copper, iron, lead, mercury, silver, 
zinc, phosphorus; narcotic poisons; irritant vegeta- 
ble poisons: poisonous meat, fish, cheese: animal 
venom ........ 375 

Index -......-. 333 



DOMESTIC SCIENCE. 



PART I. 

AIR AND VENTILATION, WITH CHAPTERS ON 
HEATING AND LIGHTING. 



CHAPTER I. 



SOME PHYSICAL PROPERTIES OF AIR. 

Existence of the Atmosphere. — it is generally 

believed that the earth's surface is covered to a depth 
of several miles by a gaseous substance known as air or 
atmosphere. Owing to its transparency, this covering 
is not apparent to our powers of sight ; there are 
however, other means by whj^h we may become con- 
vinced of its existence. When 
the air is in motion, it gives 
rise to the phenomenon of 
winds ; and the speed with 
which the moving air travels 
determines the difference be- 
tween the pleasant zephyr, 
and the destructive hurricane. 
The following simple opera- 
tion will conclusively prove 
the existence of the atmos- 
phere : 

Place a cork on water con - 
tained in a large bowl or other convenient vessel ; take 
now a tumbler or a goblet, and while holding it verti- 
cally, with the open end downward, lower it over the 
floating cork, pressing downward until the glass is 
submerged. As the cork does not rise within the 
glass, we know that the water has not entered. 




rig 1. 

Air preventing entrance of 
water. 



12 



DOMESTIC SCIENCE. 



Now, a very simple, yet proper question is, what 
keeps the water from filling the inverted goblet? 
Liquids, it is correctly said, show a tendency to seek 
their levels. There must be something inside the 
glass, which presses against the water, and prevents 
its entrance. Had it not been for the pressure ex- 
erted by this invisible something, the water would 
have risen to the same height within the vessel as 

without, or until the glass 
was entirely filled. This 
may be made much clearer 
^ by another experiment : — 
Take an ordinary lamp 
chimney, which of course, 
is open at both ends. While 
holding it in a vertical 
position, push the chimney 
into the water as was done 
with the tumbler in the for- 
mer experiment. The liquid 
will stand at the same level inside and outside the 
chimney. The water, in this case, pushes the air 
from the open glass, and takes its place. If the 
chimney had been previously filled with smoke from a 
bit of burning rag, or thick, coarse paper, the move- 
ments of the escaping air, as it overflowed the chimney, 
would be clearly visible. 

Impenetrability of Air.— The following very beau - 
tiful illustration of the impenetrability of air is suitable 
for the lecture table, and can be performed by anybody 
who will provide himself with a few simple requisites 




Fig 2. 

Water expelling air. 



PHYSICAL PROPERTIES OF AIR. 



13 



in the way of apparatus, and who will exercise a mod- 
erate degree of patience and perseverance. In the 
figure, A represents a wide -mouth bottle, capable of 
holding a pint or more; this is provided with a 
tightly fitting cork, through which two holes are 
bored. B is a funnel -tube passing through one of 
the perforations in the cork ; a piece of wide glass 
tubing could be employed, though less conveniently, 
instead of the funnel tube. C represents a delivery 




Fig. 3. 
Impenetrability of Air. 



tube of glass ; this may be easily shaped from a piece 
of glass tubing of the required length, first softened 
in a lamp flame. D is a basin or any suitable vessel 
containing water, beneath the surface of which the de- 
livery tube C terminates. E is an ordinary bottle, 
which is to be first filled with water, then inverted 
over the end of the delivery tube, and there supported 



14 DOMESTIC SCIENCE. 

on any convenient stand, or held in position by the 
experimenter. 

Now, as water is poured through the funnel tube 
into the bottle, air is forced therefrom, and escapes 
through the delivery tube into the inverted vessel. It 
may be shown by measurement, that just as much air 
is crowded out as water is poured in. Thus we see 
that this transparent, invisible air possesses in its own 
degree many of the properties of other heavier 
matter. It occupies a definite amount of room, and 
prevents other things occupying that space at the same 
time, 

Weig'ht of Air. — The atmosphere also possesses 
weight. By carefully weighing a closed vessel filled 
with air, and then weighing it again after the air has 
been drawn out by means of a pump, the weight of 
air has been accurately determined. By such means it 
has been found that a cubic inch of dry air at the 
surface of the sea weighs .31 grains. A hundred 
cubic inches would weigh therefore 31 grains; and a 
cubic foot would weigh 535.68 grains, or about 1.11 
ounces. About 14.4 cubic feet of dry air would be 
required to weigh a pound. A sitting room of 
ordinary size, say 14 feet long, 12 feet wide and 9 
feet high, would contain nearly 105 pounds of air ; and 
a large room suitable for public assemblies, say 40 feet 
by 40 feet, and 18 feet high, would hold about a ton 
of air. 

Effect of Altitude on Weig'ht of Air. — These cal- 
culations apply only to air at the sea level ; at greater 
altitudes the atmosphere is less dense, so that fewer 



PHYSICAL PROPERTIES OF AIR. 



15 



J. 



particles are contained in a given space. At the 
altitude of Salt Lake City, a cubic inch of dry air 
weighs only .26 grains; a cubic foot weighs .93 
ounces; and 17.2 cubic feet weigh one pound. 

Elasticity of Air. — An interesting demonstration 
of the elasticity of the atmosphere may be made with the 
apparatus shown in figure 4. A hollow 
body, which is best made of glass or 
porcelain, and which, as in the figure, 
may be shaped like a balloon, is immersed 
in water within a tall glass cylinder. The 
balloon is partly filled with water, the 
remaining space being, of course, oc- 
cupied by air. A very small hole near 
the lower end of the balloon permits 
water to pass in or out. A piece of 
sheet rubber is tied over the mouth of the 
jar. Any pressure applied on the 
rubber is transmitted by the water to 
the air confined in the balloon ; this air 
becomes compressed, and consequently 
more water enters the balloon, which 
therefore sinks. When the pressure 
on the rubber top is removed, the elastic- 
ity of the air in the balloon expels the excess of 
water ; and the balloon rises. 

Pressure of Liquids. — it is well known that liquids 
exert a definite pressure on bodies immersed in them. A 
forcible demonstration, which may readily be per- 
formed by ocean voyagers, is as follows : A stout bottle 
is tightly corked, and then attached to a long cord, 



Fig. 4. 

Showing 

elasticity of 

air. 



16 



DOMESTIC SCIENCE. 



weighted, and thrown overboard, the string being 
paid out as fast as the bottle sinks. Atter a considera- 
ble depth has been reached, the cord is drawn in. In 
most cases, the cork will be found forced into the 
bottle through the great pressure of the water. If, 
however, the cork used was of the "Tom Thumb" 
pattern, so that it could not enter, the bottle may be 
crushed. 

Atmospheric Pressure. — in an analogous way, 

the air presses upon every 
object on which it rests. 
To demonstrate : Com- 
pletely fill a drinking 
glass with water; lay over 
the top a piece of glazed 
note paper ; hold the 
latter firmly in position 
by placing the palm of 
the hand over it, and 
invert the vessel. The 
pressure of the air will 




Figs. 
Upward pressure of the air. 



hold the paper in position against the mouth of the 
glass after the hand has been removed, and in spite of 
the weight of the water which rests upon the paper. 
This is illustrated in figure 5. 

This demonstration may be very prettily varied by 
first tying a piece of coarse muslin over the top of the 
glass. The vessel is to be filled with water, covered 
with a piece of paper, and inverted as before. If the 
paper be then carefully drawn away, the water is still 



PHYSICAL PROPERTIES OF AIR. 



17 



kept within by the upward atmospheric pressure, 
which is exerted on the water within the vessel ; while 
the bottom of the rigid glass receives the downward 
pressure, but does uot communicate it to the liquid 
within. The upward pressure therefore operates with- 
out the downward pressure to counter- balance it. 

Another experiment should follow : Instead of a glass 
vessel use a common fruit can, the cover having been 




Fig. 6. 
Atmospheric pressure. 

removed, a piece of muslin tied over as before, and a 
small hole punched in the opposite end, as shown in 
the illustration, figure 6. Now place the finger over 
the small opening ; fill the vessel with water, cover 
with a piece of glazed paper, and invert as before. 
When satisfied that the pressure of the air sustains the 
water within the can, remove the finger, and im- 
mediately the liquid flows out, the downward 
atmospheric pressure being communicated to the con- 
tents of the vessel through the tiny aperture. This 



18 DOMESTIC SCIENCE. 

downward pressure with the weight of the water added, 
is evidently greater than the upward pressure of the 
atmosphere alone. The latter is overcome, and there- 
fore the liquid falls. 

Expansion of Air by Heat. — An interesting 

demonstration may be made by taking a hard-boiled 
egg, from which the shell has been carefully removed. 
A bottle, with a mouth sufficiently large to partially 
but not completely admit the egg, is to be provided. 
Place now in the bottle a bit of burning paper ; or hold 
within it by means of tongs a "live" coal. The effect 
of the heat is to expand the air, causing much of it to 
pass entirely out of the bottle. Now put the egg in 
position, like a stopper within the mouth. As the air 
within the bottle cools, it contracts ; the outer air, in 
its endeavor to enter the bottle, presses on the 
egg, and forces it inward, frequently with a loud 
report. 

The expansion of air by heat may be further 
illustrated in this way : Take a small cup, burn a bit 
of paper within it, or hold a glowing coal by tongs as 
in the case of the egg and bottle experiment, des- 
cribed above. The air becomes heated and expanded, 
and a portion is driven out. Now remove the fire, 
and press the mouth of the cup on the fleshy part of 
the arm. As contraction by cooling occurs, the ex- 
perimenter is made aware of a strong, and even 
painful tendency of the flesh to enter the vessel. This 
is a crude illustration of the surgical operation of 
cupping, which was in general use years ago. By 



PHYSICAL PROPERTIES OF AIR. 



19 



such means, blood and other matter could be drawn 
from an affected part of the body without the use of 
the lancet. 

The Air Pump. — Many other demonstrations, 
no less instructive than impressive, may be made by 
the aid of an Ai7' Pump. The essential points in the 




Fig. 7. 
Air Pump. 

construction of this useful instrument will be under- 
stood by reference to the cuts. Figure 7 shows the 
complete instrument. C is the cylinder, within which 
a piston works, operated by the lever L. As the 
piston is raised, air is drawn from the large globe or 
receiver R on the left. The mode of operation will be 
seen by a study of figure 8, which shows the air pump 



20 



DOMESTIC SCIENCE. 



in section. A valve, C, is connected with the piston, 
within the cylinder ; a second valve, B, is situated at 
the bottom of the cylinder ; these valves open only 
in an upward direction; a tube. A, leads from the 
receiver -plate to the cylinder. As the tightly -fitting 
piston is raised, air passes through the tube A, opens 
the valve B, and fills the space between the piston and 
the bottom of the cylinder. With the first down- 
stroke, the air confined within the cylinder becomes 
compressed, it forces open the piston valve, and 
escapes. In subsequent strokes more air is drawn 

through the tube 



"b 




A, and a globe 
or receiver plac- 
ed upon the plate 
over the en- 
trance to A 
would soon be- 
come exhausted. 
In figure 7, E 
represents an exit 

tube, which conducts the air from the upper part of 

the cylinder. 

Hand-glass Experiments. — As an impressive 
illustration of atmospheric pressure, place a hand glass, 
which is simply a hollow cylinder open at both ends, 
over the aperture in the air pump plate ; now cover 
the upper opening with the hand. As the air is ex- 
hausted, the hand is firmly held against the vessel. 
A piece of sheet rubber may be tied over the 



PHYSICAL PROPERTIES OF AIR. 



21 




Fig. 9. 
Sheet rubber under pressure. 



open glass ; as shown in 
figure 9 ; as the air is drawn 
out the rubber is forced 
into the jar so as almost 
entirely to cover the in- 
side. If instead of the 
rubber, a piece of bladder 
be tied over the jar, the 
air pressure from above 



will burst the bladder inward with a loud report. 




Fig. 10. 
Magdeburg hemispheres. 

The Mag'debupg' Hemisphepes furnish a still more, 

striking effect of atmospheric pressure. These are two 
hollow half globes, made to accurately fit each other at 
the edges. The air is exhausted from within by attach- 
ing the pair to the air pump ; after which the stop -cock 
is turned to prevent a re-entranceof air. The pressure 
of the atmosphere is so strong, that very great force is 
required to pull the hemispheres apart. (See figure 
10.) The apparatus derives its specific name from the 
fact that the first experiment of the kind is supposed 
to have been made at Magdeburg, by Otto von 
Guericke, in 1654. It is said that he used hemispheres 
so large and effective, that after the air had been 



9 



DOMESTIC SCIENCE. 



exhausted, twenty horses were unable to pull them 
apart. 

Air Supporting' a Column of Liquid. — Take a 

bottle, till it completely with water, place over the 
opening a plate of glass, invert it with its mouth just 
below the surface of water in a larger vessel, as in 
figure 11. The water remains in the bottle, though it 
stands far above the level in the outer vessel ; it is held 
there by the downward pressure of the air which is 
received on the surface of the liquid in the outer 




Fig 11. 
Air pressure supporting a column of water. 



vessel, and thence transmitted to the contents of the 
bottle. It is very readily seen, that as the mouth of 
the inverted bottle is below the surface of the water 
in the larger vessel, air could not enter the bottle from 
without, even if the contained water could be with- 
drawn. This phenomenon was discussed as long ago 
as the days of Aristotle, the noted Grecian philosopher, 
who has been dead now about twentv-one centuries. 



PHYSICAL PROPERTIES OF AIR. 23 

He taught the people, thai ^'■Nature dislikes a 
vacuum.''^ By "vacuum" is meant an empty space, 
one that is devoid even of air. 



REVIEW. 

1. Describe an experiment to prove the existence of the 
atmosphere. 

2. Describe experiments to prove that air is impenetrable. 

3. How may the weight of the atmosphere be demonstrated? 

4. Give illustrations of the weights of measured quantities of 
air. 

5. Compare the weights of equal volumes of air at the sea 
level and at the altitude of Salt Lake City. 

6. Explain the difference. 

7. How would you prove that air exerts pressure? 

8. Demonstrate the expansion of air by heat. 

9. Explain the surgical operation of " cupping." 

10. Sketch the principal parts of the air pump, and explain the 
operation of the instrument. 

11. Describe and explain the hand glass experiment. 

12. Explain the operation of the Magdeburg hemispheres. 

13. Describe a demonstration of air pressure supporting a 
column of water. 

14. How did Aristotle attempt to explain this phenomenon? 



24 



DOMESTIC SCIBNCE. 



CHAPTER 2. 

SIMPLE INSTRUMENTS UTILIZING ATMOSPHERIC PRESSURE. 

Atmospheric Pressure Measured. — We may 

very properly ask if there be a limit to the supporting 
power of the air ; or if the atmospheric pressure which 
sustains the water in the bottle, as described in the 

preceding chapter, would 
be able to hold a column of 
liquid of indefinite height. 
This question has been 
answered by experiment. 
If at the sea level we could 
take a tube, say thirty-six 
feet long, and closed at one 
end, fill it with water, and 
invert it with its open end 
beneath the surface of 
water, the liquid would 
sink to the level of thirty - 
four feet, leaving a vacuum 
in the upper part of the 
tube for the space of two 
feet. This fact caused 
Pjo. ^2. Galileo, who lived in the 

Air pressure supporting column earlier part of the seven- 
of mercury. ^^gj^^y^ century, to gravely 

assert: "Nature does not dislike a vacuum beyond 




ATMOSPHERIC PRESSURE. 25 

thirty -four feet.'- The true explanation evidently is 
that the air pressure is just powerful enough to sup- 
port a column of water thirty-four feet high. If a tube 
be filled with mercury (quicksilver), and inverted in a 
vessel of the same liquid, the column will be sustained 
at the level of thirty inches. If the tube be longer 
than thirty inches, the mercury will fall to that level, 
and a vacuum will be formed in the upper part, as 
illustrated in figure 12. Now mercury is 13.6 times 
heavier than water; and 34 feet, which is the height at 
which the water column may be sustained, is 13.6 times 
30 inches, which latter is theheight at which the mercury 
column stands. In other words, a column of mercury 30 
inches high, would weigh the same as a column of 
water of equal diameter 34 feet high. Here then is a 
very convenient method of measuring the pressure of 
the atmosphere. Suppose the tube used in the experi- 
ment with quicksilver described above, has a cross-sec- 
tion of 1 square inch; the mercury stands 30 inches 
high, therefore the tube contains 30 cubic inches of 
the liquid ; and this amount of mercury is found by 
trial to weigh about 15 pounds. We may conclude, 
therefore, that the pressure of the air is equal to 15 
pounds per square inch. 

Effect of Altitude on Aip Pressure. — This last 

statement, however, is strictly true only under the con- 
ditions prevailing at the sea level ; for the atmospheric 
pressure is found to vary greatly at different altitudes. 
The higher we proceed above the level of the sea, the 
less becomes the air pressure. By carefully noting at 
different stations the height at which the mercury 



26 



DOMESTIC SCIENCE. 



stands in a tube arranged as described above, the 
relative altitudes of those places may be determined 
with fair accuracy. At a height of four miles above 
the sea level, the mercurial column would be about 
half its ordinary height, or fifteen inches; and at an 
elevation of twenty miles it is supposed the pressure 
would not support a column higher than one inch. 
At the altitude of Salt Lake City, the mean height of 
the mercurial column is 25.6 inches; this corresponds 
to a pressure of 12.8 pounds per square inch. At this 
altitude, the body of a man of medium size, possessing 
2000 square inches of sur- 
face, would sustain a 
weight of 25,600 pounds, 
or 12.8 tons; at the sea 
level such a person would 
be under a pressure of 
30,000 pounds, or fully 15 
tons. However, as there 
is air within the body, this 
enormous pressure is 
equally balanced. 

The roof of the large 
Tabernacle at Salt Lake 
City measures 42,500 
square feet ; the air pres - 
sure thereon amounts to 
39,168 tons; at the sea 
level, with the mercurial 
column at 30 inches, such a surface would be under an 
atmospheric pressure of 45,900 tons. 




Fig. 13, 

Showing fluctuations of tiio 

mercurial column. 



ATMOSPHERIC PRESSURE. 



27 



The Barometer. — Such an instrument as that 
already described, — a tube of proper length filled 
with mercury and inverted in a cistern of the same 
liquid, is usually called a Barometer, the term meaning 
"weight measurer." Many different forms of bar- 
ometers are now in use ; the most accurate being the 
mercurial barometer similar in principle to the kind 
already described. To demonstrate the effect of vary- 
ing air pressure on the barometric 
column, proceed as follows, (see figure 
13) : Invert a barometer tube filled with 
mercury in a bottle of the same liquid. 
Provide a doubly perforated cork, which 
tightly tits the bottle mouth ; insert the 
cork with the inverted tube passing 
through, and place a short tube in the 
other perforation. By blowing through 
the short tube, an increased pressure is 
exerted on the mercury within the 
bottle, and the column rises. By 
applying suction, some of the air is 
drawn from the bottle, the pressure up- 
on the contained mercury is lessened, 
and the column falls. Thus we 

may see illustrated within a room such 
barometric differences as exist between 
the mountain -top and the sea -level. 

Siphon Barometer. — A very good 

instrument is the siphon barometer, 

illustrated in figure 14. This consists of a glass tube 



l';T 



Fig. 14. 

Siphon bar 

ometer. 



28 DOMESTIC SCIENCE. 

of proper length, bent upward at the bottom so as to 
form two arms of unequal length. The short arm is 
open, the long arm closed. When the tube is filled 





Fig. 15. 
Wheel barometer. 



ATMOSPHERIC PRESSURE. 



29 



with mercury and inverted, a vacuum is formed in the 
upper part of the long arm, the height of the liquid 
column depending upon the prevailing atmospheric 
pressure. The tube is permanently graduated above 
and below a point, selected near the middle of the long 
arm and marked zero (0). The height of the column 
is determined by reading the level of the mercury in 
the long arm above 0, and that in short arm below 0, 
and adding the two readings. 

An interesting variation in the siphon form of bar- 
ometer is the Wheel Barometer, the operation of which 
will be understood from figure 15. Resting on the 
mercury in the short arm of the tube is a float, which 

rises and falls with the 
liquid. By means of a 
string and pulley, these 
movements are communi- 
cated to an axis upon 
which a needle is fixed. 
This needle moves in 
front of a graduated disc 
on which the different 
states of the weather, 
such as "change," 
"stormy,'' 
' ' e tc . , are 




Fig. 16. 
Aneroid barometer. 



"fair," 



' rai n , 
marked. 
Aneroid BaPOmeter. — Another very convenient 
instrument is the so-called aneroid barometer, (figure 
16), in general shape not unlike a watch. The air 



30 DOMESTIC SCIENCE. 

pressure is transmitted from a very thin and flexible 
metallic casing to a system of levers acting upon the 
dial finger. The dial is graduated to correspond with 
a standard mercurial barometer.* 

The Barometep and the Weather. — Even at a 

fixed station the barometric reading is seldom constant 
for any great length of time, from which fact we learn 
that the atmospheric pressure is continually varying. 
Sudden and violent weather changes are usually 
accompanied by fluctuations in the barometric column. 
But the common belief that a decreasing pressure, as 
indicated by a fall in the barometric height, is an in- 
fallible indication of approaching storms, and that a 
"rising barometer" is surely indicative of fair weather, 
can scarcely be relied upon. We have not yet 
mastered the true science of weather indications. The 
wind still "bloweth where it listeth," irrespective of 
our artificial rules. Our confidence in the barometer's 
indications should not be impaired on this account. 
That little instrument simply informs us of changes 
in atmospheric pressure ; if we interpret such infor- 
mation to mean rain, wind, or fair weather, we do so 
of our own accord : the barometer told us no such 
thing. 

The so-called Storm Glass. — There is an instru- 



*The wor d aneroid means literally, "without moisture," and is 
applied to this form of barometer because no quicksilver or other 
liquid is used in its construction. A good aneroid is a sensitive 
instrument, even capable of shoAving the difference in atmos- 
pheric pressure between a table top and the floor beneath. 



ATMOSPHERIC PRESSURE. 



31 



ment known as the storm glass, 
now in common use. It consists 
of a sealed tube containing a 
chemical solution, in which crys- 
tals appear with varying profusion. 
It is plain that the pressure of the 
air can in no way affect the con- 
tents of the tube, as the latter is 
hermetically sealed. The author 
has made systematic observations 
on a number of the instruments, 
and finds then entirely unreliable 
as indicators of atmospheric pres- 
sure. The solvent power of the 
contained liquid is affected by 
changes in temperature, and the 
instrument has a stronger sem- 
blance to claim as a thermometer 
than as a barometer. The "storm 
glass" is well designed as a selling article and as a 
wall ornament. 

Syring'e and Pump. — The pressure of the atmos- 
phere is turned to practical account in the con- 
struction and operation of many simple instru- 
ments, among which the pump is prominent. An 
essential feature of the pump is illustrated by the 
common syringe. In figure 18 a vessel of water is 
shown ; in it are inserted two cylinders, each pro- 
vided with a tightly -fitting piston and a convenient 
handle. In the figure on the left, the piston is at the 




Fig. 17. 
Storm glass. 



32 



DOMESTIC SCIENCE. 



bottom of the cylinder ; in the right hand sketch the 
piston is partly raised, the water following it. 

The Lifting' Pump, (figure 19) consists essen- 
tially of a barrel containing a piston and valves, oper- 





Fig. 18. 
Syringe. 



Fig. 19. 
Lifting pump. 



ated by means of a lever handle. A pipe passes from 
the pump barrel to the well. At A is placed a valve, 
so constructed as to open only upward. Any pres- 
sure received from above tightly closes the valve. 



ATMOSPHERIC PRESSURE. 



33 



other valves similar in action are placed in the piston 
at B. As the piston ascends, the water follows it, 
owing to the pressure being relieved within the barrel, 
while the atmosphere 
presses with ordinary in- 
tensity on the water sur- 
face in the well. The 
force of the inflowing 
water is sufficient to force 
open the valve A. As 
soon as the down stroke 
of the piston begins, how- 
ever, the pressure closes 
the barrel valve, while the 
water forces up the piston 
valves, and fills the space 
above the piston. This 
water is lifted to the 
spout at the next up- 
stroke. 

Limits of Efficiency 
in Lifting Pumps. — As 
before explained, the at- 
mospheric pressure at the 
sea level is about 15 




Fig. 20. 
Force pump. 



pounds to each square inch, and this is sufficient to raise 
and sustain a column of water 34 feet high. Under 
the most favorable circumstances therefore, if the full 
pressure of 15 pounds to the square inch were real- 
ized, water could not be drawn by a lifting pump 
from a greater depth than 34 feet; and in actual 



34 



DOMESTIC SCIENCE. 



practice, through imperfect action of the pump, this 
theoretical efficiency is never attained. Lifting pumps 
are seldom able to draw water more than 28 feet. 
This is equal to a little more than 12 pounds to the 
square inch. At this altitude (Salt Lake City) under 
exceptionally favorable circumstances, lifting pumps 




Fig. 21. 
The Dropping Tube or Pipette. 

may draw water from a depth of 22 feet; but as a 
rule, IS feet is considered a maximum, and 16 feet 
is the general limit of efficiency. 

Force Pump. — if it be desired to lift water 
to a greater height than this, a force pump must 
be employed. This device (figure 20) is provided 
with a solid piston and a pair of valves ; one valve 



ATMOSPHEKIC PRESSURE. 



35 



A being set in the barrel, as in the case of the 
lifting pump, and the other, B being connected with 
a discharge pipe, through which the water is driven 
by the down stroke of the piston. The limitations to 
the operation of the force pump lie in the strength of 
the material from which the pump is constructed, and 
in the power applied. 

The Dropping" Tube, op Pipette, is based on the 

application of air pressure (see figure 21). Bj^ applying 
suction at one end, while the other end is immersed in 
liquid, the tube may be filled ; the finger then being so 
placed as to close the upper opening, the liquid can be 
held in the tube and be allowed to escape as de- 
sired. Such tubes may easily be made from ordi- 
nary glass tubing (figure 22.) Pipettes will be 
found of great service in many simple operations 
of the household, such as the measuring of flavoring 
extracts, medicines, and the like. 

A 




Fig. 22. 
Simple Pipette. 



Fig 23. 
The Siphon. 



The Siphon (figure 23) consists essentially'of a bent 
tube, with arms of unequal length. If the short arm, 
C A, be inserted in any liquid, and suction be applied 



36 



DOMESTIC SCIENCE. 



at the end of the long arm, A B, the liquid may be 
drawn through the tube, and will continue to flow 
after the suction has ceased.* This simply device may 




Fig. 24 . 
Siphon triuisferiing liquid without disturbing sediment. 




Fig. 25. 
Siphon transferring liquid without disturbing top layer. 



*If the siphon be filled with liquid,the ends closed, and the short 
arm inserted in a vessel of liquid, a flow will take place without 
suction being applied. The explanation of the siphon in opera- 
tion is simple. When the tube is filled with liquid the upward 
atmospheric pressure is equal at the ends B and C, (fig. 23.) But 
this upward pressure is diminished in the long arm by the weiglit 
of the liquid column A B,and in the short arm by the weight of the 
column A C. Evidently there will be a lower upward pressure at 
B than at C ; hence the flow is started from C toward B ; and if the 
end C be placed beneath the surface of a liquid, the flow will con- 
tinue as long as C is immersed, or until tlie li(iuid stands at the 
same level in the two vessels. 



ATMOSPHERIC PRESSURE. 37 

be made of much practical service in the kitchen and 
the cook-room. Liquids may be drawn off in a clear 
condition without disturbing bottom sediment (figure 
24), or top scum (figure 25). Milk may be taken 
from the setting pans without disturbing the cream, 
by inserting the tube beneath the cream layer. 



REVIEW. 

1. At what height will the atmospheric pressure at the sea 
level sustain a column of water ? 

2. At what height may a column of mercury be supported 
by atmospheric pressure at the sea level? 

3. Explain fully how the atmospheric pressure per square 
inch may be determined. 

4. At what height may a mercurial column be supported by 
air pressure at the altitude of Salt Lake City ? 

5. Give illustrations of the atmospheric pressure on the body 
of a man at the altitude of Salt Lake City and at the sea level. 

6. Sketch apparatus and explain a demonstration of varying 
air pressure on a column of mercury. 

7. What is a barometer? 

8. Name the principal kinds of barometers with which you 
are acquainted. 

9. Describe and explain the siphon barometer. 

10. Describe and explain the wheel barometer. 

11. Explain the operation of the aneroid barometer. 

12. What do you know of the barometer as a foreteller of 
weather changes? 

13. What do you know of the so-called storm glass? 

14. Explain the operation of the common syringe. 

15. What is a pump? 

16. With what classes of water pumps are you acquainted? 

17. Sketch and explain the lifting pump. 

18. The force pump. 

19. State the theoretical and the practical working distance of 
lifting pumps at Salt Lake City, and at the sea level . 

20. Sketch, describe, and explain the pipette. 

21. Explain the action of the siphon. 



38 DOMESTIC SCIENCE. 



CHAPTER 3. 

COMPOSITION OF THE ATMOSPHERE. 

Constituents of the Atmosphere. — Until com- 
paratively recent times, the atmosphere was supposed to 
be elementary in its composition, that is, composed of 
hut one simple substance. Now, however, it is known 
to be made up ot several components, the most plenti- 
ful ingredients being Nitrogeyi^ Oxygen, Carbon 
Dioxide, and Watery Vapor. The first two, namely, 
nitrogen and oxygen, are present in much the largest 
proportions, there being about four-fifths or 80 per 
cent, nitrogen and one -fifth or 20 per cent, oxygen. 
The carbon dioxide and the watery vapor are present 
in very small and variable quantities. In its condition 
of ordinary purity, the air contains about one cubic inch 
of carbon dioxide per cubic foot. 

It has been calculated that if the atmosphere could 
be compressed to a total depth of five miles, the vapor 
of water being condensed to the liquid form, and the 
atmospheric constituents being arranged in separate 
strata, the relative amounts would be shown as fol- 
lows : The water would form a sheet over the earth 
about five inches deep, above this would be a layer 
of carbon dioxide thirteen feet in depth, then a stratum 
of oxygen nearly one mile deep, and lastly, one of 



COMPOSITION OF AlK. 



39 



nitrogen four miles in thickness. Such an illustration 
is intended for comparison only ; the constituents of 
the air are not so separated ; on the contrary, there is 
a most intimate mixture of all, the heavy and the 
light ingredients being mingled at the surface in prac- 
tically the same way as at the greatest heights. 

Diffusion of Gases. — This perfect mixing is 
brought about by the operation of that wonderful law 
of nature, called by man the "Law of the diffusion of 
gases." To illustrate, we may perform the following 
experiment: Let us take two large bottles placed 
mouth to mouth, (as in figure 26), the 
upper one containing a very light gas, 
dry hydrogen for instance, and the 
lower one a comparatively heavy gas, 
ordinary air will answer. In a very 
short time, part of the heavy gas will 
have risen into the upper bottle, and a 
portion of the light gas will have sunk 
into the vessel below, and the two 
will be uniformly mixed. We can 
easily determine that the air and the 
hydrogen have become mixed, by separat- 
ing the bottles and applying a flame to 
the mouth of each ; an explosion occurs. 
Neither pure hydrogen nor air is explosive of itself, 
but a mixture of air and hydrogen explodes with vigor 
when a flame is applied. Now, air is about 14^ times 
heavier than hydrogen; yet the tendency toward 
diffusion is so strong that the heavy air rises and the 




Fig. 26. 

Diffusion of 
gases. 



40 



DOMESTIC SCIENCE. 



light hydrogen sinks till a perfect intermixture is 
effected. 
Uniformity of Atmospheric Composition. — 

By such a process of diffusion, the composition 
of our atmosphere is rendered practically uniform 
throughout. Air has been analyzed from mines and 
deep valleys, as well as from mountain tops ; from 
above the sea as well as from the land surface, and 
from the upper deeps of the atmospheric ocean as 
reached by balloon ascents ; yet the only differences 
thus far discovered are such as are due to accidental 
contamination ; the proportions of the essential in- 
gredients being practically constant in all cases. 

We should learn something regarding the individual 
characteristics of each of the principal ingredients of 
the atmosphere. 

Nitrogen ; its Preparation. — Nitrogen is the 

substance present in greatest quantity. This is a 

colorless gas, without 
appreciable taste or 
odor. It may be pre- 
pared in a compara- 
tively pure state by re- 
moving the oxygen of 
the air, and this can 
be done through com- 
bustion. Provide any 
convenient stand, as 
shown in illustration, 
(figure 27). This must be set in a bowl of water, 
so as to project several inches above the water surface. 




Fig. 27. 
Preparation of nitrogen. 



COMPOSITION OF AIR. 41 

Place on the top of the stand a bit of phosphorus* 
about the size of a No. 3 shot. Light the phosphorus 
by touching it with a heated wire, and then quickly 
invert over it a large wide-mouth bottle, which is, of 
course, filled with air. Lower the bottle over the 
burning phosphorus so as to keep the mouth of the 
vessel sealed by the water. Dense white clouds appear 
in the bottle ; these consist in reality of a fine 
white powder, formed by the union of the burning 
phosphorus with the oxygen of the air within the jar. 
After a short time, this powder dissolves in the water, 
and the bottle is found to contain about one -fifth of 
its full capacity of water, which has risen from below ; 
the remaining four -fifths are occupied by a colorless 
gas ; proper tests will prove this to be nitrogen. 

Relative Amounts of Oxygen and Nitrogen in 

the Air. — The fact that the bottle becomes about one- 
fifth full of water is significant. As- the burning 
phosphorus removed the oxygen of the inclosed air by 
uniting with it to form phosphoric acid, which was dis- 
solved in the water, evidently the space formerly 
occupied by the oxygen would be left unfilled, unless 
the water passed in. As one -fifth of the space 
originally occupied by the air is found filled with water, 



♦Phosphorus should be used only by those who have some 
knowledge of its properties. It is intensely poisonous and very 
readily inflammable. In fact, it must be kept always under water, 
and even while being handled it must be covered with water to 
prevent its taking fire. The fumes of burning phosphorus are 
very injurious, and phosphorus burns in the flesh are deep and 
painful. 

2 



42 DOMESTIC SCIENCE. 

it is clear that one -fifth of the original substance has 
been removed ; and this amount must have been the 
oxygen. The remaining gas, four-fifths in amount, 
is nitrogen. When the contents of the bottle have 
become entirely clear, we may place a plate of glass 
under the mouth of the vessel, remove from the bowl, 
and invert. 

Some Properties of Nitrogen. — if now a burning 

taper or a flaming splinter be introduced into the bottle, 
the flame will be immediately extinguished, thus prov- 
ing the inability of nitrogen to support combustion. 
A further experiment has been performed, but we need 
not repeat it; it is cruel, though it embodies a lesson. 
If a small animal, a mouse, for instance, be placed in a 
bottle of nitrogen, the little creature quickly dies with 
all evidences of suffocation. Nitrogen, then, is a 
passive, inert gas, incapable of supporting combustion 
or of sustaining life. Its chief value as an ingredient 
of the atmosphere seems to be that of a dilutent for the 
more vigorous oxygen associated with it. 

Preparation of Oxyg'en. — Oxygen, the second 
ingredient of the atmosphere in point of abund- 
ance, is not so easily prepared in a state of 
purity. The removal of the nitrogen of the air, so as 
to leave the oxygen in a pure state, is almost an im- 
possibility. But other methods of obtaining the gas 
may be employed : — Make an intimate mixture of 
potassium chlorate and manganese dioxide ; place the 
same in a flask A, provided with a delivery tube C, and a 



COMPOSITION OF AIR. 



43 



collecting bottle B, connected with a pneumatic trough,* 
as shown in figure 28. 




Fig. 28.. 
Preparing Oxygen. 

Now apply heat to the flask. Soon a gas is delivered 
through the tube with considerable rapidity ; this gas 
is oxygen. 

Some Propepties of Oxyg-en. — if a lighted taper 

or splinter be introduced into the oxygen, the flame is 
greatly increased in brilliancy. A bit of phosphorus, 
when lighted and introduced into oxygen, burns with 
blinding brightness. A piece of steel wire may be made 
to burn in this gas as easily as a shaving of wood. In 
demonstrating the combustion of metallic wire, a bit of 
wood is to be first fastened to the wire and lighted ; 
the wire then takes fire from the wood. An animal 
placed in pure oxygen gives signs of feverish exhilara- 



* A vessel to be used in collecting gases as is the bowl in figure 
3 and in figure 27, is called n pneumatic trough. It may consist of any 
convenient vessel for holding water, having a shelf or blocks for 
the support of the receiving vessel, which is to be inverted over 
the end of the delivery pipe. 



44 DOMESTIC SCIENCE. 

tion, and if compelled to breathe the gas for any great 

length of time the creature dies of excessive excitement. 

Oxyg-en and Nitrogen Compared. — A greater 

chemical contrast could scarcely be found than that 
which exists between inert nitrogen and active oxygen. 
If the oxygen were taken from the air, men and 
animals would speedily die of suffocation ; if the air 
consisted of pure oxygen the tissues of our bodies 
would soon be worn out, and death would result from 
the unnatural energy of the vital processes. In an 
atmosphere of undiluted oxygen, a combustion once 
started would soon become universal : the metal of 
our fire-places would burn with the fuel, and nothing 
would escape the general conflagration but that which 
had already been burned. The fact that combustion 
is possible in the air, points to the presence of oxygen ; 
the additional fact that such combustion is far less 
energetic than in pure oxygen, suggests the presence of 
a diluting ingredient, such as nitrogen. 

Carbon Dioxide— Mode of Preparation.— 

Carbon dioxide is itself a compound substance, consist- 
ing of the elements carbon and oxygen. It may be pre- 
pared for study by pouring a strong acid on marble, or 
on sodium carbonate, and catching the escaping gas. A 
bottle is to be provided with a doubly perforated cork, 
carrying a funnel tube and a delivery pipe arranged as 
in figure 29. In the bottle a tablespoonful of marble 
dust, or better still, the same quantity of baking soda, 
is to be placed. A little dilute muriatic acid is to be 
poured through the funnel tube upon the marble dust 



COMPOSITION OF AIR. 



45 



or soda. A gas is given off with vigor, and may be 
collected as was the oxygen, over the pneumatic trough. 




Fig. 29. 
Preparation of carbon dioxide. 



Some Properties of 




Fig. 30. 
Touring carbon dioxide. 



Carbon Dioxide — If a 

lighted taper be intro- 
duced into a vessel con- 
taining carbon dioxide, 
the flame is extinguished 
as speedily as if plunged 
into water. A living 
animal placed in the gas 
dies very speedily after a 
few ineffectual gasps for 
relief. This carbon dioxide 
is considerably heavier 
than air. The gas may 
be poured from one vessel 
to another, as shown in 
figure 30. It may be 
dipped by a small vessel 
from a larger one as 



46 



DOMESTIC SCIENCE. 



readily as water. Owing to its great weight, the 
gas may be collected, as illustrated in figure 29, by 
displacement instead of over water. The delivery tube 
in such a case is to be passed to the bottom of the 
collecting bottle. A lighted candle held at the mouth 
will be extinguished as soon as the vessel is filled. If 
we continue to pass the gas into a vessel after the latter 
has become full, the gas will run over as water would 

do under similar circum- 
stances. True, the sub- 
stance is transparent and 
colorless, and therefore 
entirely invisible, but a 
candle flame held alongside 
the receiving vessel will 
reveal the overflow (see 
figure 31). 

Carbon Dioxide from 
Fermentation. — The 

writer once visited a large 
vinegar factory in the State of Maryland. The vats in 
which the mash was placed to ferment were each as large 
as a sitting room. These vats were only half filled with 
mash, the upper space being left for the gathering of 
the carbon dioxide which is given off in the process of 
fermentation. On the occasion of the visit referred to, 
a double quantity of mash had by mistake been 
pumped into one of the large vessels. There was, of 
course, no room for the carbon dioxide to collect, and 
it ran over the sides of the vat as fast as produced. 
Several workmen who were engaged in repairing the 




Fig. 31, 
Carbon dioxide overflowiii 



COMPOSITION OF AIR. 4 7 

floor around this particular vat were quickly enveloped 
in the suffocating gas, and died before assistance could 
be rendered. 

Tests fOP CaPbon Dioxide. — Its power of ex- 
tinguishing a flame is a usual method for determin- 
ing the presence of carbon dioxide ; but it will be 
remembered that nitrogen possesses the same property. 
A more reliable test may be made as follows : — Prepare 
a little clear lime water, by adding water to good lime 
and afterward filtering. Pour a little of this into a 
bottle containing carbon dioxide ; then shake. The 
lime water becomes at once milky from the formation 
of insoluble lime carbonate, resulting from a union 
of the lime and the carbon dioxide. By exposing a 
dish of lime water to the atmosphere, with occasional 
shaking, after a time a turbid appearance is produced, 
indicating the presence of carbon dioxide, which must 
have existed in the air. 

Watery Vapor in the Air. — The existence of 
vapor of water in the atmosphere is a fact scarcely to 
be wondered at. If a vessel of water be exposed freely 
to the air, after a short time the liquid is found to 
have disappeared. The particles of water have not 
oeen destroyed. They have, in fact, been lifted into 
the air by the process of evaporation, and there they 
float as freely as the other constituents of the atmos- 
phere. A very simple proceeding will prove the pres- 
ence of watery vapor in the air about us. 

Provide a glass of ice water for observation. See 
that the outside of the vessel is perfectly dry. Set the 
glass in a warm room, and observe. In a short time 



48 DOMESTIC SCIENCE. 

the outside of the glass becomes covered with drops of 
liquid looking not unlike dew. This moisture must 
have come from the atmosphere of the room. Under 
all circumstances water can be condensed from the 
atmosphere if the temperature be sufficiently lowered. 

Capacity of Aip for Moisture ; Saturation. — 

— The quantity of moisture which the air can absorb 
and hold in suspension depends largely upon the 
temperature. Warm air has a much greater capacity 
for moisture than has cold air ; and the process of 
cooling the air results in the deposition of much" of 
the water which it held. When the air contains all 
the moisture it is capable of holding at any given tem- 
perature, it is said to be saturated. At the freezing 
point of temperature, (32° F.) the air is saturated with 
moisture when it contains 2.3 grains of water to the 
cubic foot. At 60° F. a cubic foot of air will hold 5.8 
grains of moisture ; at 90° F. it will hold 14.3 grains ; 
and at 100° F. it may contain 19.1 grains. In the 
cold season, therefore, the air may appear moist be- 
cause it is near its saturation point, though in reality it 
contains at such time much less moisture than under 
conditions of greater warmth. Evidently the drying 
power of the atmosphere will depend upon its capacity 
to take up more moisture than it already holds. It is 
customary to express the drying power of the atmos- 
phere in degrees, the determination being made by 
finding the difference between the temperature of the 
air and the dew point. 

Air Overcharg-ed with Moisture. — When under 

any circumstances the air becomes charged with 



COMPOSITION OF AIR. 49 

moisture beyond its point of saturation, some form of 
precipitation is the result. The deposit may occur in 
the form of dew, or, if larger quantities of water are 
condensed at the time, as by a sudden cooling of a 
heavily laden cloud, the fall may be one of rain, snow, 
or hail, as the temperature may determine. 

Summapy. — Let it be remembered then that the 
air contains four essential, constant ingredients: — 
7iitrogen, oxygen,, carbon dioxide^ and vapor oftvater; 
and beside these, several other accidental constituents, 
such as gaseous emanations from decaying matter, the 
volatile materials of fuel, the aroma of flowers, and 
the like. The nitrogen and the oxygen form the bulk 
of the atmosphere. These are present in the propor- 
tions here shown : — 

BY WEIGHT. BY VOLUME. 

Oxygen 23.1 per cent. 20.9 per cent. 

Nitrogen 7G.9 " " 79.1 '• " 



100. 100. 

The average quantity of water present in the at- 
mosphere is perhaps nearly 1 per cent, and that of 
carbon dioxide is about Y2000 of the air by weight. 



REVIEW. 

1. "What is a chemical element? 

2. Name the substances present in the atmosphere . 

3. State the relative amounts of these ingredients present in 
the atmosphere . 

4. Explain the law of the diffusion of gases. 



50 DOMESTIC SCIENCE. 

5. Show the operation of this law upon the atmosphere. 

6. How would you separate nitrogen from the other atmos- 
pheric ingredients? 

7. Describe the principal physical properties of nitrogen. 

8. Describe the chief chemical properties of nitrogen. 

9. How would you prepare oxygen for experimental pur- 
poses? Sketch the apparatus you would employ. 

10. Describe a series of demonstrations of the power of oxygen 
in supporting combustion . 

11. Compare oxygen and nitrogen as to their chemical prop- 
erties. 

12. What is a chemical compound? 

13. How would you prepare carbon dioxide for experimental 
purposes? 

14. How would you demonstrate that carbon dioxide is heavier 
than air? 

15. Describe the principal chemical properties of carbon 
dioxide. 

16. Describe a chemical test for the presence of carbon 
dioxide. 

17. Demonstrate the existence of watery vapor in the atmos- 
phere. 

18. Show the effect of varying temperature on the capacity of 
the atmosphere to hold moisture. 

19. What is meant by the air being saturated with moisture? 

20. Explain dew point. 

21. Explain the drying power of the atmosphere. 



PERMANENCY OF THE ATMOSPHERE. 51 



CHAPTER 4. 

PERMANENCY OF THE ATMOSPHERE. 

Conditions of Change in Atmospheric Con- 
stituents. — The uniform and constant composition 
of the atmosphere appears all the more remarkable, 
when we consider the many influences of change to 
which most of the ingredients are subject. As has 
been already seen, the nitrogen of the air is an inert 
constituent ; though mixed with other substances, it 
takes no part in the transformations which they so 
readily undergo. Air is taken into the lungs of men 
and animals, and though the oxygen is there ex- 
changed for carbon dioxide, the nitrogen passes out 
again in an unchanged state. In all lires, oxygen 
combines with the fuel, and thus adds to the energy 
of the blaze, but the nitrogen remains still passive and 
free. The oxygen and the carbon dioxide, however, 
are continually undergoing change by an endless series 
of rapid combinations and decompositions. Let us, 
then, turn our attention to these. 

Effect of Respiration on Air Composition.— 

In breathing, men and animals inhale by drawing a 
portion of air into the lungs ; and after an interval, 
they exhale or expel about the same quantity of gase- 
ous matter, though of a composition far different from 
that taken in. Expired air contains more carbon 



52 



DOMESTIC SCIENCE. 



dioxide, and a far lower proportion of free oxygen 
than does air before respiration. Blow through a 
small tube, a straw will answer well, into a vessel of 
clear lime water : the milky appearance (see chapter 
3, — carbon dioxide) indicates the presence of carbon 
dioxide in the breath. This is true of the breath of 
animals as well as of human beings. When we strive 
to think of the number of living beings constantly 
breathing, and thus removing oxygen from the air and 
supplying carbon dioxide thereto, the causes of the 
permanency of the atmosphere become still more per- 
plexing. 
Oxygen Supplied to the Air. — it would seem to 

us at first thought, that after a time all the oxygen of 
the air would be consumed, and in its place would be 
a superabundance of the deadly carbon dioxide. Be- 
side the respiration of animal bodies, there are many 

other causes by which 
atmospheric oxygen is 
consumed and carbon 
dioxide produced ; such 
as the combustions in 
lights and fires, the de- 
cay of organic matter, 
and all common pro- 
cesses of fermentation. 
In some portions of the 
earth, vast volumes of carbon dioxide are thrown into 
the air from volcanic fissures and rents, from car- 
bonated mineral springs, and the like. It is calculated 
that over 300,000,000 tons of coal are annually 




Fig. 32. 
Leaves exhaling oxygen. 



PERMANENCY OF THE ATMOSPHERE. 53 

burned in the world under present conditions. 
This alone would produce upward of 800,000,000 tons 
of carbon dioxide gas. A century ago but an in- 
significant fraction of this amount was consumed ; 
yet the composition of the atmosphere seems not to 
have been altered by this immense supply. There 
must be some powerful influences in operation, 
through which oxygen is restored to the air and 
carbon dioxide abstracted therefrom. An experiment 
on this subject was made in 17 74 by Dr. Priestly, an 
English chemist, and it has been repeatedly verified 
since that time. Each of us may make the demon- 
stration his own by proceeding as follows (see figure 
32) : Place a sprig of green leaves, freshly plucked, 
in a bell jar or large bottle, and fill the vessel so as to 
cover the leaves with water that has been charged with 
carbon dioxide. Then invert the bottle in a larger 
vessel of water, place the whole in direct sunlight, 
and watch results. Very soon, bubbles of gas are 
seen rising from the leafy surfaces ; and these bubbles, 
being lighter than the water, collect at the top of the 
bottle, the heavier liquid sinking to give them space. 
When a sufficient quantity of gas has been collected, 
place a piece of glass beneath the mouth of the bottle, 
and set the' vessel right side up. Now introduce a 
lighted candle or splinter into the gas ; the increased 
brilliancy of the flame declares the substance to be oxy- 
gen. The carbon dioxide with which the water was or- 
iginally charged has disappeared in the process: It is 
therefore clear to us, that, under the influence of sun- 



64 DOMESTIC SCIENCE. 

light the leaves have absorbed the carbon dioxide, and 
have exhaled oxygen in its place. 
Carbon Dioxide Removed from Air by 

Plants. — If compelled to re -breathe their own ex- 
halations, animals would soon die for want of oxygen ; 
yet the foulest emanations of animals' lungs, the 
suffocating carbon dioxide, forms the chief support of 
the plant. Under the influence of sunlight, the green 
leaves of plants, through their multitudes of tiny 
pores, draw in the carbon dioxide from the at- 
mosphere, and exhale the life-giving oxygen. Says 
Professor Johnson, "On a single square inch of the 
leaf of the common lilac as many as 120,000 breath- 
ing pores have been counted ; and the rapidity with 
which they act is so great that a current of air passing 
over the leaves of an actively growing plant is almost 
immediately deprived of the carbonic acid it contains." 
And again, "A common lilac tree, with a million of 
leaves, has about four hundred thousand millions of 
pores or mouths at work, sucking in carbonic acid ; 
and on a single oak-tree as many as seven millions of 
leaves have been counted." 

Chlorophyle-bearing Plants; Fungi. — This 
power of the leaves is exerted only under the in- 
fluence of sunlight, direct or diffused. The active 
principle of the leaf, by which the decomposition of 
carbon dioxide is effected, is technically known as 
chlorophyle, a word meaning " leaf -green," and so 
used because the substance is usually of a green color, 
and b)"^ its presence imparts the prevailing hue to 
foliage. The word scarcely expresses the whole nature 



PERMANENCY OF THE ATMOSPHERE. 

of this potent compound, for in the case of multi- 
colored leaves, as for example, the petals of flowers, 
the varied tints are apparently imparted by a substance 
identical in most respects other than color with the 
chlorophyle of green leaves. Plants that contain no 
chlorophyle, (fungi), such as the mushroom, toad- 
stool, and the like, exhibit none of the colors of the 
higher plants, and they flourish when entirely deprived 
of light. Such jjlants do not decompose the carbon 
dioxide of the atmosphere, but they exhale this gas, 
and consume oxygen as do animals. 

House Plants. — Chlorophyle-bearing plants, when 
deprived of light act somewhat similarly to the fungi, 
thus rather vitiating than purifying the air. In the 
open air, the carbon dioxide evolved during the 
hours of darkness by growing plants has but slight 
effect upon the purity of the atmosphere ; but 
in closed spaces, as the rooms of houses, the result is 
different ; and therefore it is considered injurious to 
sleep in rooms containing growing house -plants. 
Though during the bright hours, these beautiful 
growths are alike pleasing in their effects upon the 
mind and body, in darkness they tend, however 
slightly, to increase the contamination which is so 
constant a feature of animal and human existence. 

Ag-ency of Plants in Drying" the Soil. — in 

marshy districts, growing plants exert another in- 
fluence of great benefit, since by the absorption of 
water through their roots they aid in drying the soil. 
The sun-flower and the eucalyptus tree haVe been used 



56 DOMESTIC SCIENCE. 

ill experiments of the kind with very satisfactory 
results. 

Carbon Stored in the Earth. — if we have read 

at all aright concerning the past history of our earth, 
there was a time at which the decomposition of carbon 
dioxide through the agency of plant life took place on 
a scale vastly greater than that of the present. In 
that period of the earth's growth which is known as 
the Carboniferous Age, one of the preparatory stages 
through which the earth passed before it was fitted for 
animal life, the air was strongly charged with carbon 
dioxide. At that time, however, vegetation flourished 
on the earth with a luxuriance far beyond any 
comprehension based on present circumstances. In 
that age there existed extensive forests of mammoth 
ferns, gigantic club-mosses, and huge trees of many 
strange growths. All lived by decomposing the 
carbon dioxide of the air, fixing its carbon, and 
returning its oxygen in the gaseous state. That carbon 
has ever since been buried deep in the stony fastnesses 
of the globe, there undergoing change until converted 
into coal.* Of the importance of coal, but little need 
be said. AVithout it, the world could not be what it is 
today. Now, by burning the coal, its carbon unites 
once more with oxygen to form carbon dioxide, and 
thus the air receives again the substances taken from it 
through the subtle agency of plant life ages ago. 



*Read cbapter id, "A Talk about Coal," in the author's "First 
Book of Nature." 



PERMANENCY OF THE ATMOSPHERE. 57 

Carbon Dioxide Removed by Certain Animals. 

— But lest the carbon dioxide should become too plen- 
tiful for animal welfare, the Creator has wisely directed 
other influences to operate in again removing this in- 
gredient of the atmosphere as fast as it is produced. 
Go walk upon the sea beach, and there watch the mol- 
lusks, great and small — shell fish as we usually term 
them — living in such profusion ; observe them care- 
fully, and see what they are about. The stone-like 
shell forming the creature's home, consists principally 
of calcium carbonate : and of this substance two -fifths, 
or forty per cent., is carbon dioxide. Then let us sail 
into warmer climes, and there observe the myriads of 
coral polyps so successfully fighting the battle of life 
with the angry breakers of their ocean home. The 
substance that we ordinarily call coral is indeed no- 
thing but the shell in which the tiny creatures lived ; 
and this shell is composed mainly of calcium carbon- 
ate taken from the waters, and containing the propor- 
tion of carbon dioxide already named. The beauti- 
ful marbles which man ever has delighted to polish 
and admire, and the massive limestone pillars, but- 
tresses of the mighty hills — are made also of calcium 
carbonate, holding its proportion of carbon dioxide 
imprisoned by the powerful bonds of chemical force.* 

Mutual Dependence of Animals and Plants. 

— Upon such a plan does the Creator maintain the 
equable balance of the elements. Is it not wonderful 



* Read chapter 40, " About Limestones," in the " First Book of 
Nature." 



58 DOMESTIC SCIENCE. 

that the animal, in the unconscious exercise of its own 
vital processes, contributes to the support of the hum- 
ble plant? And the plant is not unmindful of the aid 
thus received. The field of growing corn, while pre- 
paring aliment for the support of a higher life, the 
rose bush perfecting its flowers with which to please 
the eye, adorn the home, and inspire the heart of man, 
the vine laboring to ripen its tempting clusters, each, 
all are purifying the atmosphere, and preserving the 
equilibrium without which animal life would soon 
cease to exist on earth. What, then, is independent 
in nature? The mighty oak, and the gay squirrel 
which finds food and shelter beneath the hospitable 
branches of the tree, are mutually dependent. Neither 
the animal nor the plant can say to the other, "I have 
no need of thee." Each has been prepared by its Cre- 
ator to be a support to the other. Could any power 
possessing aught less than infinite wisdom have 
planned and executed so perfect, so admirable a 
design ? 



REVIEW. 

1. What do you know of the changes through which the 
atmospheric constituents are constantly passing? 

2. Show the effect of animal respiration on the composition 
of air. 

3. How is the supply of atmospheric oxygen maintained? 

4. How is the carbon dioxide prevented from becoming ex- 
cessive in the atmosphere? 

5. Describe a demonstration of the effect of growing plants 
yielding oxygen to the air. 



PERMANENCY OF THE ATMOSPHERE. 59 

6. What do you know of the number of breathing pores on 
leaves? 

7. Define "chlorophyle." 

8. State a use of chlorophyle in plants. 

9. Define and illustrate "fungi." 

10. What is your opinion [of the good or ill effects of keeping 
growing plants in living rooms? 

11. State what you know of the Carboniferous Age. 

12. Show the effect of corals and mollusks in removing carbon 
dioxide from the atmosphere. 

13. What do you know of marbles and limestones as holders of 
carbon dioxide? 

14. Show the mutual dependence of animal and plant life. 



60 DOMESTIC SCIENCE. 



CHAPTER 5. 



THE AIR OF ROOMS. 



Air of Closed Rooms. — The contaminating 
influences to which the atmosphere is subject through 
human and animal respiration, have been ah'eady re- 
ferred to. The atmosphere of closed rooms shows the 
effects of such influences to a much greater extent than 
does the open air, for the chief reason that enclosed 
air possesses far less opportunity of purifying itself. 
Combustion of lights and fires within the room, and 
the respiration of the inmates, work together in con- 
suming oxygen and producing carbon dioxide. 

Contamination of Air by Human Beings. — 

But this is not the only change. Large quantities of 
water, in the form of vapor, are being continually 
thrown into the air, from the lungs and the skin of 
living beings. That this is true of the lungs may be 
demonstrated by breathing upon any cold polished 
surface. To prove that the same statement applies to the 
skin, the following simple experiment may be made: 
Take a large dry bottle, with the mouth sufiiciently 
wide to admit your hand. See that the hand is clean 
and dry, and introduce it into the bottle; then wrap 
a cloth around the wrist to seal the mouth. After a 
short time, the inside of the bottle becomes dimmed 
with moisture, which increases till it gathers in drops 



THE AIR OF ROOMS. 61 

and trickles down the sides of the vessel. The skin 
over the whole body is pierced with innumerable tiny 
openings, through which vapor is continually escaping, 
unless these pores have become closed through un- 
cleanliness or disease. As a result of numerous 
experiments, it is believed that the quantity of fluid 
matter escaping in one day from the skin of an adult 
person, is not less than from two to three pounds.* 

Foul Matter from Exhalation. — But this 

liquid excretion from the skin and the lungs is not 
pure water ; it is indeed strongly charged with the 
products of animal decay. By way of proof as to the 
impure nature of the liquid matters in the breath, 
proceed in this way : Take a clean dry bottle, having a 
wide neck : hold it before your mouth, and breathe 
into it for some time. Then close it tightly, and set 
it in a warm place for an hour or so ; after this, re- 
move the stopper, and apply the nose with critical 
care. A foetid odor will be experienced ; most prob- 
ably of a convincing strength. f 

*Dr. Faraday, of well merited fame, said upon this subject: 
—"I think an individual may find a decided difference in his 
feelings when making part of a large company, from what he does 
when one of a small number of persons, and yet the thermometer 
may give the same indication. When I am one of a large number 
of persons, I feel an oppressive sensation of closeness, notwith- 
standing the temperature may be about 60 degrees or 65 degrees, 
which I do not feel in a small company at the same temperature, 
and which I cannot refer altogether to the absorption of oxygen, 
or the inhalation of carbonic acid, and probably depends upon 
the effluvia from the many present." 

t Such putrescible matter is constantly formed in the air of in- 
habited rooms; it settles upon the walls and furniture and its 
thorough removal, if indeed at all possible, is a difficult under- 



62 DOMESTIC SCIENCE. 

A few years ago, an experimenter caused a num- 
ber of persons to breathe through tubes into a closed 
vessel surrounded with ice, by which means the vapor 
of the breath was condensed in considerable quantity. 
Some of this liquid was injected into the blood vessels 
of dogs and other animals. The process was followed 
in almost every case by speedy death of the victims 
with all appearances of poisoning. 

Service Rendered by the Sense of Smell. — 

Though the organs of smell are of wondrous deli- 
cacy in enabling us to detect the presence of foul or 
offensive matters, the sense may be easily dulled, so 
that we become oblivious to the most disgusting 
odors. Note the sickening effect which one experien- 
ces on re-entering a close bedroom, after having been 
in the open air for a time, though perhaps the person 
may have occupied that room during the entire night 
in complete unconsciousness of its foul condition. It 
is proper that every person should seek to preserve the 
delicacy of each of his senses. No power of sensation 
has been implanted within the human organism with- 
out a definite use and purpose for the benefit of the 
possessor. It is probable that we do not comprehend 
the full purpose of the power of smell ; yet it is easy 
to perceive how we are warned against inhaling many 
poisonous emanations, through their disagreeable 



taking. Upon these offensive substances those natural and 
necessary scavengers, tlie greatly abused house-flies, largely feed, 
and but for these useful little creatures Ave Wf>uld be in a still 
worse plight. 



tHE AIU OF ROOMS. 63 

odors. Though there are some gaseous poisons which 
are utterly devoid of odor, nearly all fcetid and dis- 
gusting smells indicate the presence of poisonous 
matters.* 

Danger from Unclean Surrounding's. — 
Many serious disorders have been directly traced to the 
breathing of the foul gases arising from decaying 
matters. The close proximity of stables, cow-houses, 
pig-pens, and the like, is a constant menace to the in- 
mates of any house so situated. However, contami- 
nation of the air from such causes may surely be 
detected by a keen sense of smell. t 

Foul Emanations in Wet Localities. — in 

wet localities, quantities of the injurious carhuretted 
hydrogen (marsh gas) originate from the rotting 
matters in the soil, and though this gas is itself with- 



*The delicacy of the sense of smell in detecting inconceivably 
small particles of matter diffused through the air, is illustrated 
by the oft-ciuoted statement of Dr. Carpenter:— "A grain of musk 
has been kept freely exposed to the air of a room, of which the 
doors and windows were constantly open, for a period of ten 
years, during all which time, the air though constantly changed, 
was completely impregnated with the odor of musk, and yet, at 
the end of that time, the particle was found not to have sensibly 
diminished in weight." 

t " The offensive trades mentioned in the Public Health Act of 
1875" (England) " are those of blood-boiler, bone-boiler, fell- 
monger, soap-boiler, tallow melter, tripe-boiler. The model 
byelaws of the local Government Board include in addition, those 
of blood-dryer,leather-dresser, tanner, fat melter or fat-extractor, 
glue -maker, size-maker, and guit scraper, as being trades for 
which regulation by sanitary authority is desirable." — ParJces. 
These occupations are all attended by foul odors, and such pur- 
suits the sanitary authorities of England have found it advisable 
to restrict. 



64 DOMESTIC SCIENCE. 

out odor, yet when arising from such source it is 
always associated with ill smelling gases. 

In such localities, too, and more especially in 
volcanic regions, and in the vicinity of " sulphur 
springs," the air is rich in sulphuretted hydrogen, 
sometimes called from one of its very un -inviting 
sources, " rotten -egg gas." It is characterized by a 
most disgusting odor, and when inhaled even in small 
quantities produces severe headaches, nausea, and 
general prostration ; and in large amounts it induces 
a stupefying effect, which may terminate fatally. This 
substance is a constituent of the gases of sewers, and 
sometimes it finds its way into dwellings from defect- 
ive drain pipes ; there, by its soothing effect upon the 
inmates, its i^resence is to their senses imperceptible, 
though its effects are positively deadly. 

Carbon Dioxide Exhaled by Human Being's. — 

Having seen that contamination of air in our dwell- 
ings is constantly taking place, it is of interest to 
inquire as to the rate at which such processes are 
operating. Many attempts have been made to deter- 
mine the average quantity of air vitiated by the res- 
piration of a single person during a specified length of 
time ; but the results are widely different owing to 
to the varying rapidity of the breathing act, and the 
absence of uniformit)'^ in lung capacity. We may 
safely say, however, as the result of numerous and 
elaborate experiments, that an adult person of average 
size in a state of rest, ordinarily expires 0.6 cubic foot 
carbon dioxide per hour. The amount of this gas 
naturally present in the outer air is found by analysis 



THE AIR OF ROOMS. 65 

to be about 0.04 per cent., or 0.4 parts per thousand. 
From the experimental labors of Dr. Chaumont and 
others, we learn that a disagreeable smell is perceptible 
in the air of rooms as soon as the carbon dioxide has 
reached 0.06 per cent., or 0.6 parts per thousand.* 
This amount, which is 0.2 parts per thousand above 
that contained iu pure air, is considered by reliable 
authorities as the maximum quantity to be tolerated in 
the air of inhabited rooms. 

Rate o! Contamination from Human Res- 
piration — Suppose an adult person to be confined 
in an air-tight inclosure containing 3000 cubic feet of 
space. In an hour he would give to the inclosed air 
0.6 cubic foot of carbon dioxide; this added to the 
amount of the gas present in pure air would make the 
total quantity 1.8 cubic feet, thus: — 0.6+ (0.4 x 3= 
1.2)= 1.8. This being distributed among 3000 cubic 
feet would represent 1.8^-3=0.6 cubic foot per thou- 
sand, and here we see the permissible limit is exactly 
reached. In order to keep the air within this limit of 
impurity, during a second hour 3000 cubic feet of 
fresh air should be admitted to replace the contamin- 
ated air of the chamber. 



*The bad smell here referred to is not due to the carbon 
dioxide itself, this being an odorless gas, but arises from the foul 
organic matters of the expired air, and these contaminating in- 
gredients increase in proportion to the carbon dioxide. As no 
strictly accurate methods of determining the amount of such 
putrescible substances have been devised, it is a rule with 
chemists to determine the carbon dioxide in the air under ex- 
amination, and then to estimate the amount of organic matter 
from this result. 



66 DOMESTIC SCIENCE. 

Amount of Aip Required for Efficient Ven- 
tilation. — From such deductions as the fore- 
going, it is stated by many authorities, that to be 
proj)erly ventilated a dwelling house should receive 
3000 cubic feet of fresh air per hour for each of its 
inmates. This amount may seem excessive ; yet in 
determining it, no allowance has been made for the 
many contaminating influences beside the exhalations 
of the occupants. Dr. Billings places the requisite 
supply of air at one cubic foot per second, or 3600 
cubic feet per hour. If fires and lights are burning 
in the rooms, additional allowance in the supply of 
fresh air should be made. It is not possible to make 
an accurate measurement of each of the many sources 
of contamination ; it is necessary, therefore, to make 
liberal allowance for deficiencies in providing for the 
air supply of houses. The more closely we can cause 
the air within doors to approach in composition the 
atmosphere without, the more beneficial will be its 
effect upon health. Children expire a lower propor- 
tion of carbon dioxide than do adults. Persons en- 
gaged in physical exertion exhale much more than the 
ordinary amount ; sick people require a greater supply 
of fresh air than is indispensable to the healthy. It is 
therefore plain to us that buildings used for different 
purposes require varying allowances for the proper 
supply of air. 

Illustrative Examples. — At the rate of contami- 
nation already stated, the air in an ordinary bedroom, 
say 12 by 14 by 11 feet, containing 1848 cubic feet of 
space, would be contaminated by the exhalations of a 



THE AIR OF ROOMS. 67 

single occupant in a little less than 37 minutes. A 
school room 28 by 35 by 14 feet would contain 13,720 
cubic feet of air. Suppose such a room to be occupied 
by 60 children, allowing each of them only 2000 
cubic feet of air per hour, the contained atmosphere 
would become vitiated in less than 7 minutes. For- 
tunately for most of us, the doors and windows of 
ordinary dwellings are seldom made to close tightly ; 
consequently they permit some passage of air, and 
the evil results of neglect in ventilation are delayed 
beyond the theoretical indications. 

The Amount of Space necessary to the well be- 
ing of the inmates of a room is a subject requiring 
attention. If the space be made inadequately small, the 
entrance of a proper amount of air within a given 
time may cause injurious draught.* The figures 



* Parkes has furnished us the following good illustration : "For 
instance, suppose in a dormitory occupied by 10 persons the 
amount of space per head is only 300 feet; to supply 3000 cubic 
feet of fresh air per hour, 30,000 cubic feet must be admitted in 
this period, and the air of the room will be completely changed 
10 times, a proceeding which would cause in cold weather, unless 
the entering air was warm, a most disagreeable draught, for the 
cold air could not be properly distributed before reaching the 
persons of the occupants. But if the cubic space per head be 
1000 cubic feet, then the air of the dormitory need be changed 
only 3 times per hour, and if such renewal is effected steadily 
and gradually, the cold entering air is broken up, and mixing 
with the warm air of the apartment creates no draught." The 
same author has drawn attention to the necessity of providing 
adequate floor space for each individual; "for," says he, "if the 
height of the room is much over 12 feet, excess in this direction 
does not compensate for deficiency in the other dimensions, 
although the total cubic space may be the same; thus it wovild 
not be the same thing to allow a man 50 square feet of floor space 
in a room 20 feet high, as to allow bim 100 square feet of floor 



68 DOMESTIC SCIENCE. 

already given as indicating the necessary supply of 
fresh air are based upon the investigations of many 
leading authorities. On this subject however there is 
a wide discrepancy of opinion, and some writers give 
figures which by comparison would seem dispropor- 
tionately low.* It is well to set our ideal conditions 
of atmospheric purity fairly high, and then approach 
them as closely as the prevailing conditions may per- 
mit. 

Ill Effects of Cellars under Houses. — Another 

prolific source of contamination to the air of 
dwellings arises from the hurtful custom of digging 
cellars beneath the fioors of houses. Cellars are 
usually damp and musty, even if nothing be stored in 
them ; but such places are commonly made receptacles 
for the most perishable products. The foul gases gen- 
erated from such decaying matter rise into the rooms 
above, carrying with them the influences of disease. 
The earth itself, near the surface, is rich in decomposa- 



space in a room 10 feet high, although the amount of cubic space 
allotted in each case would be identical. The reason is that the 
organic matters of respiration are not equally diffused through- 
out the air of the apartment, but tend to accumulate in the lower 
strata, consequently excessive height does not, in their case, 
mean a corresponding dilution." 

* Among builders there is a woeful lack of uniformity in 
ideas as to tlie requisite air supply for health. The writer has 
applied to a number of prominent architects for such informa- 
tion, some answers obtained indicated a belief in the figures 
above quoted; others gave very low estimates. One architect 
considered necessary 16.G cubic feet per minute, and one gave 4 
cubic feet per minute as a liberal estimate, adding that 4.5 cubic 
feet would be exceptionally good. Chemical analysis would 
show the air of occupied rooms so supplied, to be truly filthy, and 
buildings so constructed are far from healthful. 



THE AIR OF ROOMS. 69 

ble matters, and under the most favorable of 
circumstances the ground upon which a house rests 
becomes saturated with the emanations of the rotting 
contents of the soil. Even upper rooms though they 
may be properly plastered and floored, soon become 
foul if not thoroughly aired at short intervals. This 
is because there are many putresible substances in 4;he 
earth and upon the walls and furniture of the room, 
and the products of decomposition accumulate with 
alarming rapidity, unless adequate provisions be made 
for their removal. 

Vitiation of Aip by Combustion — if the com- 
bustion of fuel in open fireplaces and in stoves were 
thoroughly accomplished, the vitiated air would be 
removed from the room through the draught flue. In 
the case of artificial lights, however, such as candles, 
lamps, and gas flames, the products of combustion, 
together with the nitrogen gas which is left after the 
consumption of the oxygen, remain in the room. The 
.rate of such vitiating processes depends, of course, 
upon the substances burned and the rapidity of the 
combustion. By careful trials it has been found that a 
pound of good charcoal requires for its complete com- 
bustion 11 pounds of air, which amount of air would 
measure about 150 cubic feet. One pound of mineral 
coal of ordinary quality requires a little more than 
9 J pounds, or about 120 cubic feet of air. A pound 
of dry wood consumes while burning about six 
pounds, or 78 cubic feet of air. For purposes of 
illumination candles are now but little used ; their 
former place being taken by oil lamps and gas 



70 DOMESTIC SCIENCE. 

flames. Kerosene lamps vary greatly in the relative 
amounts of oil which they consume. A lamp of ordi- 
nary size will vitiate to an un breathable state between 
70 and 80 cubic feet of air per hour. 

A consideration of these facts will indicate the 
absolute necessity of providing efficient means for a 
constant supply of fresh air in dwellings. 



REVIEW. 

1. What are the principal sources of impurity in the air of 
rooms? 

2. Show the contaminating effect of human beings on the air 
of rooms. 

3. Demonstrate that foul matters are constantly being thrown 
off by the human lungs and skin? 

4. Show the value of the sense of smell in warning us against 
foul air. 

5. What do you know of the delicacy of the sense of smell? 

6. By what means is the outer air in the neighborhood of 
dwellings often contaminated? 

7. What particular contaminating ingredients are to be found 
in the air of marshy places? 

8. What do you know of sulphuretted hydrogen? 

9. Give illustrations of the rate at which contamination of 
air progresses in closed apartments. 

10. State the quantities of air needed per hour for each in- 
mate, for the proper ventilation of dwellings. 

11. Illustrate by instances of bed rooms and school rooms of 
definite sizes, the rate of contamination from the inmates. 

12. Show the hurtful effects of placing cellars beneath dwell- 
ing rooms. 

13. What effect have fires and lights on the air of rooms? 

14. Give illustrations of the amounts of air required for the 
combustion of definite weights of certain fuels. 



ILL EFFECTS OF IMPURE AIR. 71 



CHAPTER 6. 

ILL EFFECTS OF IMPURE AIR. 

The physical operations of which the Breathing 
Process consists are simple. Gaseous matter is taken 
into the lungs, and after a short time much of it is ex- 
pelled again. This ingoing and outgoing action might 
be in some degree imitated by a pair of bellows ; here, 
however, the analogy ends ; the air escapes from the 
bellows unchanged in composition or general proper- 
ties, but the air exhaled from the lungs is very different 
from that taken in. 

The Respiratory Apparatus. — Let us consider 

briefly the structure of the respiratory apparatus. A 
sketch of the principal organs is given in figure 33. 
The mouth is connected directly with a tube known as 
the trachea or windpipe, B ; this extends downward 
through the neck into the chest cavity, and there 
divides, sending a branch, called a bronchus, to each 
lung. The human lung, like every other part of the 
body, is of strange and wonderful workmanship ; yet 
simple and surprisingly efficient. The lung, when 
divested of its delicate wrappings, may be compared to 
a bag surrounding the bronchus (as at C), so as to 
appear as an expansion of this tube. By dissecting 
away the outer portions of the lung, the tube which 
enters it is seen to divide, and the branches subdivide 



72 



DOMESTIC SCIENCE. 



again and again, as at D, till they form a net work of 
tiny tubes, so minute that with our unaided vision we 
cannot follow them to their terminations. Calling the 
microscope to our aid, however, we will find that the 




Fig. 33. 
Organs of respiration. 

finest division of the bronchial tubes 1, terminate in 
expanded bladder-like inclosures, as in 2. These are 
called air vesicles, and are clustered together in forms 
suggesting bunches of grapes. A view of the air vesi- 
cles laid open is given at 3. 



ILL EFFECTS OF IMPURE AIR. 73 

Aeration of the Blood. — During the process of 
inhalation, air is drawn through the windpipe into the 
lungs, there filling and inflating the air vesicles. The 
walls of these vesicles are surprisingly thin, far more 
delicate in structure than the finest of artificial fabrics. 
Tiny arteries and veins convey the blood to and from 
these air vesicles, the vessels spreading over the sur- 
face of the vesicles, so that the contained blood is 
separated from the air only by the thin membranous 
wall already described. There is a remarkable ten- 
dency known as os7nosis, possessed by all fluids, by 
which they strive to mix with each other, even if sep- 
arated by a tolerably thick partition, providing, of 
course, that the separating medium is at all perme- 
able. 

By this property, the air that has been drawn into 
the vesicles passes through the inclosing wall and 
mingles with the blood ; and at the same time, the foul 
gases, which have been acquired by the blood in its 
passage through the system, pass into the cavities of 
the air vesicles and are expelled from the body in the 
succeeding exhalations. In this way, the blood be- 
comes aerated or purified by exchanging the gaseous 
products of disassimilation for invigorating oxygen. 
Charged with this life-giving ingredient, the blood 
again goes bounding through the body carrying vital- 
ity and energy to every part. If the effete matters 
resulting from the vital processes were left to accumu- 
late within the body, speedy suffocation would result. 
They can be removed only by efficient respiration, 

3 



74 DOMESTIC SCIENCE. 

taking place through the instrumentality of compara- 
tively pure air. 

Morbid Effects of Vitiated Air. — Scrofula. — 

The morbid effects wrought upon the system through 
the inhalation of impure or vitiated air are very varied. 
Many specific diseases, and much general debility and 
predisposition to bodily disorders have been directly 
traced to this cause. Scrofulous affections are fre- 
quently aided in this way. Ills of this class bear evi- 
dences of impaired and inefficient nutrition ; by this is 
meant the inability of the body to properly assimilate 
the elements of food and to produce therefrom healthy 
tissue. M. Baudoloque, a French physician of high 
repute and a specialist in scrofulous disorders, writes : 
"Invariably it will be found on examination that 9. 
truly scrofulous disease is caused by a vitiated air, and 
it is not always necessary that there should have been 
a prolonged stay in such an atmosphere. Often a few 
hours each day is sufiicient, and it is thus that persons 
may live in the most healthy (healthful) country, pass 
the greater part of the day in the open air, and yet be- 
come scrofulous, because of sleeping in a confined 
place, where the air has not been renewed." 

Consumption, another dread disease, which carries 
so many people to their graves, is closely allied 
in its nature to scrofula.* In consumption, or Tuber - 



*" One not very strong or unable powerfully to resist conditions 
unfavorable to health, and with a predisposition to lung disease, 
will be sure, sooner or later, by partial lung starvation and blood 
poisoning to develop pulmonary consumption. The lack of what 



ILL EFFECTS OF IMPURE AIR. 75 

culosis, as physicians term the disorder, the luDgs of 
the sufferer develop throughout their tissue, num- 
erous lumpy concretions or tubercles, which consist 
for the most part of albumen in a coagulated and 
partially organized form.* 

Sore Throat. — A special variety of sore throat, 
Tonsilitis, is recognized by the medical profession ag 
frequently resulting from the breathing of air laden 
with the products of organic decay. As this disease 
is of common occurrence among the inmates of houses 
that are provided with poorly arranged drains, causing 
a flow of impure gases from the sewer or cess -pool 
to the rooms of the house, the disorder is frequently 



is so abundant and so cheap — good, pure air — is unquestionably 
the one great cause of this terrible disease." 

Black, in " Ten Laws of Health," 

*" A great amount of phthisis (consumption) has prevailed in 
the most varied stations of the (English) army, and in the 
most beautiful climates — in Gibraltar, Malta, Ionia, Jamaica, 
Trinidad, Bermuda — in all of which places the only common con- 
dition was the vitiated atmosphere which our barrack system 
everywhere produced. And, as if to clinch the argument, there 
has been of late years a most decided decline in phthisis in these 
stations, while the only circumstance which has notably changed 
in the time has been the condition of the air." — Report of English 
Army Sanitary Commissioners (quoted by BLACK). 

" Carmichael, in his work on ' Scrofula,' gives some most strik- 
ing instances where impure air, bad diet, and deficient exercise 
concurred together to produce a most formidable mortality from 
phthisis. In one instance in the Dublin House of Industry, where 
scrofula was formerly so common ;as to be thought contagious^ 
there were, in one ward, 60 feet long by 18 feet wide, 38 beds, each 
containing four children; the atmosphere was so bad that in the 
morning the air of the ward was unendurable. In some of the 
schools examined by Carmichael, the diet was excellent, and the 
only causes for the excessive phthisis were the foul air and 
the want of exercise."— Dr. Parkes, London. 



76 DOMESTIC SCIENCE. 

called ''sewer air throat." "It is marked," says Dr. 
Parkes, of London, "by great inflammatory swelling 
of the tonsils, very foul tongue, gastric derangement, 
accompanied by severe headache and intense depres- 
sion. The temperature of the body is often not much 
raised, certainly not to a height proportionate to the 
severe symptoms ; but this low temperature, together 
with the intense prostration, are characteristic of most 
illnesses resulting from the entrance of sewer-polluted 
air or water into the system." 

Severe Dysentery is frequently caused by the breath- 
ing of contaminated air. To this is to be attributed 
the periodical occurrence of summer disorders of this 
class, which sometimes produce an alarming degree of 
mortality. These fatal results are especially marked 
among children, whose comparatively feeble vitality 
and tender constitutions can but poorly withstand the 
death -dealing influences of these foul causes. 

Mortality Among" Childpen in Iceland. — it is 

reported by travelers that the inhabitants of Iceland 
seem oblivious to the importance of ventilation in their 
snow huts. Warmth they crave, and this they may 
secure, though frequently at the expense of life. Dr. 
Youmans remarks, " We are therefore not surprised 
that in the foul and stifling air of Iceland habitations, 
two out of three of all the children should die before 
twelve days old."* 



*"The extreme cold of the winter in Iceland, reduces the sys- 
tem of domestic ventilation in that country to very primitive 
principles. A traveler there was so choked one night by the close 
atmosphere of the air-tight little chamber, in which he slept with 



ILL EFFECTS OF IMPURE AIR. 77 

Foul Aip Weakens the Entire System.— Be- 
side the few specific bodily troubles named above, out 
of the many that could be enumerated as resulting 
from the inhalation of polluted air, the same cause 
produces a general undermining of the vital powers, 
and a strong predisposition of the bodily tissues to 
disease of many kinds. All influences that tend to 
lower the bodily vitality, weaken our hold on life by 
inviting disease to take up its abode within our bodies.* 
An impoverished system is a fertile field for the ger- 
mination and development of disease germs. It is 
believed that such germs are widely distributed through 
the atmosphere, ever ready to enter the human body ; 
yet they flourish within the system only when they find 
there proper nutriment, such as the impurities attend- 
ing degenerated tissues and disorganized functions ; 
otherwise they die through lack of nourishment.! 



all the male members of the family, as to be compelled to wake 

his host, who sprang out of bed at the call, pulled a cork frora a 

knot-hole in the wall for a few minutes, and after replacing the 

cork, with a shiver returned to bed." 

Science, 1889. 

*" On the imagination of mothers, educated as well as Ignor- 
ant, the feeling still seems to be stereotyped, that the free, pure, 
unadulterated air of heaven falls upon the brow of infancy as the 
poppies of eternal sleep, and enters the lungs and circulates as a 
deadly poison; and still the shawls and blankets, sleeping and 
awake, are pretty generally employed to deprive the objects of 
the most rapturous, paternal solicitude, of what was originally 
breathed into the nostrils of the great archetype of the human 
race as the 'breath of life.' " 

(Quoted by Youmans.) 

t " It was in England that the solution of the great problem of 
hygiene was first attempted. 'Preventive Medicine' it is there 
called. Palmerston told a deputation which waited on him in 



78 DOMESTIC SCIENCE. 

Effects of Foul Air on the Mental Powers:— 

The mental powers are greatly weakened and conse- 
quently hindered in their proper exercise if foul air be 
breathed. This would be naturally expected from a 
consideration of the close relationship existing between 
the mental and the physical functions of the body. 
The brain is appropriately spoken of as the organ or 
seat of the mind ; that is to say, though the brain and 
the mind are in no sense identical, the latter is depen- 
dent for its action upon the former, just as the hand 
in writing is dependent upon the pen. Although the 
exact relationship between brain and mind are but lit- 
tle comprehended, it is known as a fact that an injury 
to the brain affects in some degree the mental faculties, 
and that a strong, well- trained mind is always asso- 
ciated with a properly developed brain. 

The brain is composed of nervous tissue, and is 
nourished by the blood in the same manner as are all 
other parts of the body. A very large proportion of 
the blood of the body passes to the brain and is dis- 
tributed over its surface through numerous minute 



order to ask him to order a fast on the approach of the second 
epidemic of cholera, to cleanse their sewers and diligently visit 
the dwellings of the poor. And he did not confine himself to 
good advice, but with his usual energy he laid his hand on sani- 
tary legislation, and purified the air of London and the large 
manufacturing towns. The result of the sanitary measures car- 
ried out was a reduction of the mortality of London from 26 to 23 
per 1,000, and in some of the towns to 17 per 1,000— a low death rate 
previously only equalled in the Isle of Wight. More than 4,000 
lives have been preserved yearly in London, and assuming that 
the mortality among the sick is 1 in 20, this number represents a 
diminution in yearly sickness to the extent of 80,000." 

Dr. Seegen. 



ILL EFFECTS OF IMPURE AIR. 79 

vessels. As a consequence, the brain is rapidly and 
strongly influenced by the state of purity in the blood, 
and as before seen, the blood is greatly affected by the 
condition of the air employed in respiration. It is clear 
then that the brain depends largely for its normal ac- 
tion upon the air that is breathed. 

Popular Disreg'apd of Requirements for 

Pure Air. — Yet how oblivious are the majority of 
people to these vital facts ! Even among the noble 
class of students, old and young, all of whom are 
supposed to be thinkers, there prevails the most de- 
plorable ignorance ; or, if not this, then the most hurt- 
ful, almost criminal negligence. The pupil at his 
books, the editor with his pen, the artist at his easel, 
and even the theologian asking for divine inspiration 
in his sacred studies, are apt to voluntarily surround 
themselves with the stifling, mephitic atmosphere of 
close-shut rooms. Unto them the air of heaven is for- 
bidden to come. 

In places for public gatherings the conditions are 
even worse. Though architects have now partly 
learned the lesson of providing adequate avenues of 
ventilation, thoughtless janitors persistently ignore the 
means supplied. In the churches and meeting houses 
dedicated to the worship of the Being who framed the 
laws of health, and who provided the means for their 
observance, places in which multitudes gather with the 
professed desire of hearing and understanding the 
word of God, the vitiated air begets dullness of intel- 
lect and torpor of spirit, and the gentle voice of divine 
inspiration is unheeded and unheard. Much of the 



80 DOMESTIC SCIENCE. 

proverbial drowsiness among the congregations of 
churches is directly traceable to the closed windows 
and shut doors of those sacred edifices. Is it other 
than a grievous sin, a mockery indeed of the Creator's 
goodness, to petition for the inspiration of His Spirit, 
and then to willfully darken our minds and bring obliv- 
ion upon our souls? The writer has been at night in 
places of worship in which the lamps burned dimly for 
want of supporting oxygen ; think you the spirits of 
those present were not correspoudingly darkened? Is 
Godliness to be attained in the midst of willful and 
persistent unclean liness? 



REVIEW. 

1. Describe the processes of human respiration. 

2. Describe the organs of respiration. 

3. Explain the effect of pure air upon the blood in the vessels 
of the lungs. 

4. State the principal diseases which are particularly favored 
by^the breathing of foul air. 

5. What do you know of scrofulous disorders being aided by 
vitiated air? 

6. Of consumption? 

7. Of tonsilitis? 

8. Show the effects of foul air in inducing general disposition 
of the bodily tissues toward disease. 

9. Give instances, from among those quoted, of the baneful 
effects of contaminated air. 

10. What have you heard of the inefficient ventilation practiced 
in Iceland, and of the high rate of mortality there prevailing 
among children? 

11. What effect has impure air on the mental powers? 

12. Explain the physiological effects of foul air upon the 
brain. 



D¥ST IN THE AIR. 81 



CHAPTER 7. 

DUST IN THE AIR. 

Dust Floating" in the Air. — The principal 
gaseous and liquid impurities of the atmosphere 
have been dwelt upon in a previous chapter, but in 
addition to the contaminating substances there named, 
there are others, consisting of finely divided, solid 
particles. The name commonly applied to this class of 
impurities is dust. Until recently, but little thought 
was bestowed upon the ill effects of these floating par- 
ticles ; of late, however, the subject has received 
greater attention. It has been conclusively proved by 
experiment and observation that the inhalation of dust- 
laden air is a potent factor in the production and 
growth of certain disorders of the respiratory organs, 
among which bronchitis, pneumonia, and phthisis are 
prominent. The presence of dust within the respira- 
tory passages will invariably produce serious results, 
owing to the irritating effect of hard particles upon the 
delicate lung tissues. 

Dust Inhaling" Occupations. — To illustrate the 

effect of dust upon the respiratory organs, let us con- 
sider briefly the effects of some particular branches of 
dusty toil. Dr. Hall tells us that the average life of 
fork grinders is about twenty -nine years, and that of 
edge-tool workers generally 'about thirty -one years, 
the cause of death in the majority of cases being lung 



82 DOMESTIC SCIENCE. 

troubles, induced through the inhaling of metallic par- 
ticles and the dust arising from the wear of the grind- 
stones. Pearl button makers suffer from such disor- 
ders to a marked extent, as do also workers of flax 
and cotton, and employes in paper factories. 

Hard and Ipritating" Dust Most Injurious. — 

An attentive review of statistics representing the com- 
parative mortality among people of different dusty 
occupations, reveals the fact that the most injurious 
kinds of dust are such as consist of hard, sharp, and 
angular pieces. Dr. Ogle, of England, has compiled 
a table* showing the mortality among British people 
(males) between the ages of twenty -five and sixty - 
five years, who are employed in certain widely different 
occupations, including those of (1) coal miners, (2) 
carpenters, (3) bakers and confectioners, (4) plumbers, 
painters, and glaziers; (5) masons and bricklayers; 
(6) wool workers ; (7) cotton workers ; (8) quarry- 
men (stone and slate) ; (9) cutlers ; (10) file-makers ; 
(11) earthenware manufacturers; (12) Cornish tin 
miners. 

Comparative Mortality among* Coal Miners 

and Tin Miners. — it is found that these trades 
stand in the order in which they are given above in 
the scale of increasing mortality among their fol- 
lowers ; that is to say, among the people employed in 
the occupations named, the English coal miner is freest 



* Published as a supplement to the Forty-fifth Annual Report of 
the Registrar-General of England. For quotations and com- 
ments see "Practical Hygiene" by Dr. Louis C. Parkes, London. 



DUST IN THE AIR. 83 

from lung disorders, and the Cornish tin -miner is of 
all most subject to such troubles. Indeed the mortality 
from lung diseases alone among the miners of tin ore 
is 3.5 times that among the coal diggers; nearly 66 
per cent, of the total mortality among tin -miners is 
due to bronchial disorders, and the death-rate among 
this class of workmen is nearly three times as high as 
that of the male population of their region considered 
as a whole. 

Dr. Ogle attributes the comparative safety* of coal 
miners in this respect, mainly to the softness of coal- 
dust particles and to the freedom of such from all 
sharp angles and points. He believes also that coal- 
dust exercises some influence in hindering the progress 
of phthisical disorders. Such comparative immunity 
from lung diseases among the miners of coal, is still 
more surprising when we consider that these men are 
kept while at work in a heated atmosphere, vitiated 
from constant emanations of noxious gases from the 
walls, ceilings, and floors of the black, subterranean 
passages, t The tin -miners on the other hand, though 

* The reader should guard himself against an exaggerated 
opinion of the safety of coal-miners. The immunity spoken of 
in the text has reference to lung diseases only, and the compari- 
son is made iwith other dust-inhaling occupations only. The 
miner of coal is certainly far naore liable to bronchial troubles 
than persons protected from all dust would be. That coal mining 
is a hazardous occupation from liability to terrible accidents 
needs no argument here. 

t Let it be remembered that these statements regarding the 
healthfulness of coal-miners are applied to the workers of British 
mines only. The laws of England regarding the ventilation of 
mines, especially coal-mines, are strict. The copious flow of air 
through the underground passage carries away noxious gases 
and dust as fast as liberated. 



84 DOMESTIC SCIENCE. 

laboring under many conditions similar to those at- 
tending the coal workers, inhale dust consisting of 
hard, sharp, and irritant particles. 

Poisonous Dust. — These examples illustrate 
the mechanical irritation on the walls of the air 
passages occasioned by dust, much of which, in a 
toxical sense, may be considered innocuous ; there 
are other occupations, however, in the course of which 
the workmen are exposed to poisonous dust. Such 
is the case with brass founders and copper-smiths, 
among whom mortality runs high from copper poison - 
ing; "brass-founders' ague'' used to be a popular 
name for disorders of this sort. Lead poisoning is a 
frequent cause of death among plumbers and painters, 
the former contracting the disease from the inhalation 
of volatalized lead and lead oxide, and the latter from 
breathing air laden with white -lead dust, and from 
absorbing through the skin the poisonous lead com- 
pounds of their paints. Mercurial poisoning causes a 
rise of mortality among all who work with the curious 
quicksilver, and arsenical fumes carry many to early 
graves from the ranks of ore roasters. 

All Dust Deleterious. — The cases already referred 
to are somewhat special in their nature, it is true ; 
comparatively few are called to labor and to suffer in 
such injurious occupations ; yet there are lessons in 
these examples which are applicable to all people. We 
learn that dust of any description is deleterious when 
introduced into the air passages of the body ; care, 
therefore, should be exercised to escape the injuries 
thus indicated. 



DUST IN THE AIR. 85 

Inhalation Througrh the Nostrils. — The Creator 

has done much to arm His children against these in- 
evitable dangers. Our nostrils are lined with stout 
hairs, vibrissoe they are called, and these act some- 
what as a sieve to the air that passes between them. 
The nose openings are the proper respiratory entrances 
to the lungs ; and much of the dust, which, if breath- 
ing be carried on through the mouth, will surely find 
its way into the deeper air passages, will be arrested 
in its course if forced to thread the intricate passages 
of the nose. When a person is exposed to dust, the 
mouth should be kept closed. 

Lining- of Respiratory Passages. — Further de- 
fense against the injuries of dust-laden air is offered 
by the peculiar structure of the lining membrane in 
the trachea and the lung passages. The inner surface 
of these channels is ciliated — that is, covered with 
innumerable hair-like outgrowths (cilia), so fine as to 
appear under the low powers of the microscope like 
the pile on new velvet. These countless cilia are in 
a state of constant motion, like waving grain under 
the influence of a gentle breeze, and as the direct 
movement is always toward the mouth, there is a 
tendency to sweep upward from the lungs all solid 
particles that may have found lodgment upon the 
walls. When the dust thus carried reaches the throat, 
a cough suggests itself, an expectoration follows, and 
the intruding particles are ejected from the body. 

Inanimate Components of Dust. — it will per- 
haps be interesting, and certainly instructive, to inquire 



86 DOMESTIC SCIENCE. 

as to the nature of common street dust. Its grittiness 
declares the presence of earthy particles, such as bits 
of pulverized stone ; this material is a natural con- 
sequence of the wear and tear of roads, and the more 
general disintegration of the rocks through natural 
agencies. But beside this purely inorganic or mineral 
matter, the microscope reveals many organic particles. 
Mingled with the structureless mineral particles are 
the siliceous shells of diatoms ; also spores of many 
of the lower plants ; fragments of straw and hay, — 
these often partly digested, proving that they must 
have traversed the alimentary tract of some herbivorous 
animal ; — grains of starch ; scales from the wings of 
butterflies and moths ; hairs of animals, and soft 
down from birds ; and bits of cotton, wool, and silk. 

Living" Organisms in Dust.— in addition to this 

varied assortment of inanimate matter, the microscope 
reveals the presence of many living organisms, whose 
minuteness is almost beyond description. Many of 
these are comparatively innocuous, though some have 
the power of producing specific diseases, provided they 
are taken into the system, and find there the nutri- 
ment necessary to their being. Such germs thrive 
within the body chiefly upon the products of deterior- 
ated tissue ; a healthy system has power to resist the 
attacks of many noxious germs by refusing to afford 
them requisite nourishment. The person who has 
ignored God's law of health, and who has weakened 
his body through injurious excesses, has little means 
of defence against the invading hosts of contagious 



DUST IN THE AlK. 87 

germs. Temperance in all proper indulgences, and 
rectitude in all the duties of life, will combine their 
unconquerable forces against the deadly foe. 

Household Dust. — Much of the outdoor dust finds 
its way into the house, and there augments the ills 
resulting from the presence of household dust proper. 
The oft -quoted illustration is conclusive proof that dust 
pervades our homes — notice the path of a sunbeam 
within a partially darkened room ; along the line of 
light innumerable "gay motes " appear, rising, sink- 
ing, with ceaseless motion, all made plain to our gaze 
by that efficient analyist, the solar beam. Professor 
Tyndall has employed the electric arc instead of sun 
light in numerous investigations, and has clearly 
shown that the air in all places near the earth's sur- 
face is heavily dust-laden. The dust of rooms com- 
prise all the ingredients of street dust, and in addition 
many other particles arising from household wear and 
tear and the varied domestic operations. Common 
among these are fibres of many kinds from the carpets 
and draperies of rooms ; crystals of salt ; finely 
divided carbon as soot, lampblack, and coal-dust; bits 
of hair and wool ; and epithelial scales from the skin 
and lungs of the inmates. Of these, the last named, 
including all organic particles* arising from the bodies 
of living beings, are most to be feared. Such organic 



*Dr, Louis Partes says of household dust: "It is thus seen to 
consist largely of organic refuse, often more or less putrescent, 
and its presence in the air assists in the production of the low 
state of health so common to the occupants of dirty, overcrowded 
houses." 



88 DOMESTIC SCIENCE. 

dust, if arising from the bodies of persons suffering 
from infectious diseases, may become the medium 
of deadly contagion. 

Dust-tPaps in Houses. — it is, of course, impos- 
sible to prevent the entrance and formation of dust 
within our homes ; the necessary wear of domestic 
operations will constantly give rise to detached parti- 
cles ; we can scarcely hope to find a dustless house. 
Our efforts would be most wisely directed if applied 
toward the prevention of undue accumulations of the 
dust, and to averting, as best we can, the ill effects of 
its putrefactive changes. Many rooms are, from their 
construction, veritable dust-traps. Uneven wall sur- 
faces, projecting door and window frames, cornices, 
ceiling and wall mouldings, all prove effective in en- 
trapping dust particles and holding the same secure 
from the broom and duster of the most energetic 
house -maid. The floors are no less instrumental in 
this respect; crevices between the boards hold 
immense quantities of dust ; heavy and immovable 
furniture renders a thorough and frequent cleansing 
scarcely possible ; but beyond all these, carpets stand 
forth as the chief of dust -catchers. 

Carpets and Curtains as Dust Holders. —The 

custom of covering every floor with woven carpets, 
which are removed only at intervals of months, is a 
deplorable one. Investigation by several English 
physicians has done much to prove this fact, and 
there are today many eminent medical practitioners 
who decline to undertake cases of illness if the 
patients are kept in carpeted rooms. Close and polished 



DUST IN THE AIR. 



89 



or oiled floors are easily cleaned ; if carpets are used 
at all they should be but lightly fastened. Indian 
matting has been recommended ; this material is but 
slightly absorbent, and admits of ready cleansing. 
Oil cloth and linoleum may be used in dry situations ; 
if the floors are exposed to dampness, *however, the 
use of such will favor the development of ''rot" in 
the wood. 

Curtains of thick fabrics, heavy draperies, wall 
hangings, lambrequins, and the like, all serve to gather 
and conceal dust. If such decorations are used at all 
they should be of light material, and be so arranged as 
to admit of ready removal and frequent cleansing. 

Poisonous Wall Papers.— Rough or "flock" 

wall papers hold large quantities of dust, and some 
such papers give off particles of pigment from their 
own surfaces. This condition is especially undesira- 
ble if the loosely applied coloring matters of the paper 
are of a poisonous nature. Much has been written 
and said regarding the presence of arsenic in wall 
papers, and the deadly effects of the poison upon the 
inmates of rooms ornamented with such papers. 
Doubtless, the use of arsenical wall paper is a source 
of serious danger, and has produced even fatal results, 
but papers of this sort are far less common than has 
been generally supposed.* The writer has collected 

* Arsenic and various other poisonous matters are used in 
coloring many kinds of paper besides tliat designed for wall 
decoration. Even tlie tinted tissue paper used for the instruction 
and entertainment of children in kindergartens, is contami- 
nated with poisonous colors, and cases of serious injury have re- 
sulted from the children's habit of chewing such paper. It may 



90 DOMESTIC SCIENCE. 

from the supply stores of Salt Lake City, and has 
analyzed 127 specimens of wall papers, of as many 
colors and kinds as could be found ; and in only four 
of them was arsenic present at all. The worst of these 
was a bright green with gilt markings ; this contained 
per square foot between 7 and 8 grains of metallic 
arsenic, corresponding to nearly 10 grains of white 
arsenic. The use of such a paper on the walls of 
dwelling rooms would be a source of great danger. 
Arsenical Poisoning" fpom Wall Paper. — 

Parkes reports the presence of arsenic in wall papers 
in quantities varying from less than a grain to even 60 
grains per square foot. The same authority has clas- 
sified the principal symptoms of arsenical poisoning 
from such cause, among which the following are 
prominent: — cough associated with nausea, diarrhoea, 
colic pains and cramps, dryness of mouth and throat 
with intense thirst, severe lachrymation, distress- 
ing headache, and a marked debility of the whole 
system, which, in extreme cases, leads to actual par- 
alysis of the limbs sometimes followed by convulsions 
and death. 

Arsenical Pigments. — Green papers are the ones 
most likely to contain arsenic, though the poison has 
been found in reds, browns, and greys. The arsenical 
compound most used as a pigment is the arsenite of 



be argued that paper should not be chewed; this is true, but 
many children will try their teeth on everything that they can 
get into their mouths. If paper contains poisonous pigments, as 
Dr. Youmans has said with a kind of grim humor, " such deadly 
additions utterly spoil the paper for dietetical purposes either 
for children or adults." 



DUST IN THE AIR. 91 

copper, commercially known as "Scheele's green," 
and composed of arsenic and copper in a combined 
form : a still more attractive tint is produced by 
the aceto-arsenite of copper, commonly known as 
" Schweinfurth green." Some arsenical papers have 
the coloring matters so loosely applied that the 
poisonous particles become detached from the paper 
and permeate the room as fine dust, thus finding their 
way into the lungs of the inmates through the process 
of respiration. In other cases, especially if exposed 
to dampness, the arsenical compounds rapidly under- 
go chemical changes whereby certain gaseous sub- 
stances are generated, the chief of which is arseniur- 
etted hydrogen — one of the deadliest of poisons.* 

Characteristics of non-injurious Wall Paper. 

— A competent chemist could determine by very sim- 
ple tests whether arsenic is or is not present in 
any samples of paper submitted to him ; if the means 
of securing such a test be not at hand when selections 
of wall paper are to be made, it would be safest to 
choose smooth papers, of light tints, with colors that 
cannot be easily rubbed off. Varnished papers are 
still better ; their colors are protected beneath a toler- 
ably impervious coat, and they admit of washing. 



*Prof. Johnson of Yale says that Schweinfurth green when 
moist gives rise to the formation of the deadly arseniuretted 
hydrogen in great quantity. He has given a detailed account of 
the poisoning of a whole family from sleeping in a house, the 
walls of which were hung with paper of this dangerous though 
beautiful tint. 



92 DOMESTIC SCIENCE. 

REVIEW. 

1. What is dust ? 

2. What effect has dust upon the respiratory passages when 
inhaled with the air ? 

3. What do you know of the unhealthfulness of certain dust- 
inhaling occupations ? 

4. Explain Dr. Ogle's example of the difference between 
English tin-miners and coal-miners in their liability to lung 
troubles. 

5. Give instances of the ill effects of dust in the case of fork 
and tool grinders. 

6. Give instances of the effects of inhaling poisonous dust. 

7. What natural barrier against the entrance of dust into 
the lungs has the Creator provided ? 

8. Explain the action of the cilia in the bronchial passages. 

9. W^hat do you know of the composition of out- door dust ? 

10. Of in-door dust? 

11. What is meant by organic dust ? 

12. Name the principal features of ordinary dwellings which 
favor the accumulation of dust. 

13. Show the effect of carpets as holders of dust. 

14. What are the dangers of poisonous pigments in wall 
papers ? 

15. What do you know of the occurrence of arsenical pig- 
ments in wall papers ? 

16. State the principal properties of a good wall paper. 



VENTILATION. 93 



CHAPTER 8. 

VENTILATION. 

Methods of Purifying" the Air of Rooms.— 

Having convinced ourselves that the atmosphere of dwell- 
ings is constantly becoming contaminated through addi- 
tions of foul and poisonous matters, it is now a matter 
of importance and interest to consider the principal con- 
ditions attending the necessary purification of the air 
of our homes. Two general modes of accomplishing 
this have been attempted. The first consists in re- 
moving the vitiated air, and admitting in its place a 
supply of fresh air from without ; this is commonly 
spoken of as ventilation proper. In the second 
method, chemical means are employed either to de- 
compose or to absorb the effete matters as fast as 
they are formed, thus maintaining in the inclosed 
atmosphere a normal state of purity ; this is known as 
the chemical method. Of each of these general pro- 
cesses there are numerous variations as to details, but 
the chemical method has had but limited application ; 
we shall therefore consider here only the more impor- 
tant methods pertaining to ventilation proper. 

Requipements in Efficient Ventilation. — in 

devising plans for the ventilation of buildings, we are 
required to provide for the removal of foul air as fast 
as formed, and for its replacement by pure air from 
without. Attention must also be paid to the tempera- 
ture of the entering air, for experiment and observation 
have shown that the introduction of large volumes of 
cold air into inhabited rooms may prove a source of 



94 DOMESTIC SCIENCE. 

serious injury. Draughts are also to be avoided, else 
ill effects will be manifest in the health of the inmates. 
The frequent changing of the air of an apartment 
involves the moving of immense masses of air, and 
some adequate power is requisite to the accomplish- 
ment of this. The means generally employed are 
dependent (1) upon the heating oj the contained 
atmosphere \ or (2) upon mechanical devices. It will 
be well to consider a few methods from each of these 
divisions. 

1. AIDS TO VENTILATION, DEPENDING UPON 

TEMPERATURE CHANGES. 

Currents Produced by Changes of Tempera- 
ture. — It has long been held as an adage that "Heat 
causes expansion, and cold causes contraction." This 
is applicable to gases as well as to solids and liquids. 
When a mass of air is warmed, its particles are driven 
farther apart, thus requiring greater space; the warmed 
air is specifically lighter than the cold, and consequently 
tends to rise ; this movement would produce an empty 
space or partial vacuum below, but the neighboring 
cold air promptly rushes in to fill such space. All 
natural movements of air, which we call winds, depend 
directly or indirectly upon this cause. Any means of 
warming and expanding the air in one place will cause 
there a rising current, and the space below will soon 
be filled with air of a lower temperature, which in turn 
will become heated, will rise, and will make room for 
other air. This principle may be well observed in the 
entering and out-going currents of a room. If the 
temperature of the inclosed air be higher than that 



VENTILATION. 



96 



without, when the door is opened the cold air will 
enter in a current near the floor, while the warmed 
and lighter atmosphere will pass out by a counter cur- 
rent at the top. To make clear the course of these 
currents, place the door ajar, (see figure 34) and hold 
a lighted candle in the opening, first near the top, and 
then below. The flame will be driven outward at the 

top, and toward the room 
at the bottom. 

On warm days of sum- 
mer, or at other times by 
artiflcially cooling the in- 
closed air, these conditions 
of relative temperature 
within and without may 
be reversed ; then the outer 
air, being warmer than the 
inclosed, would enter near 
the top of the door open- 
ing, while an out-going 
current would be estab- 
lished below. 

Opposite Currents Essential to Ventilation. 

— In the experiments just described, the width of the 
door opening permits the passage of currents in oppo- 
site directions ; with more contracted spaces, however, 
such counter currents would seriously interfere with 
and perhaps totally neutralize each other. To illus- 
trate this, provide a small flame, as that of a burning 
candle; surround this with a good sized lamp chim- 
ney, set in a shallow dish containing a little water so 




Fig. 34. 

Currents into and from a 
Avarmed room. 



96 



DOMESTIC SCIENCE. 



as to seal the bottom. The flame soon dies out, 
smothered by the non-supporting products of the com- 
bustion. Now divide the chimney passage by insert- 
ing a strip of metal, thin wood, or even of stiff paper, 
as shown in figure 36, the candle may now be kept 
burning. A bit of smouldering paper held at the top 
will show the existence of upward and downward cur- 
rents. This clearly demonstrates the necessity of 
providing separate open- 
ings as inlet and outlet 
for the air of any room. 

Ventilation in Mines. 

— Upon this simple prin- 
ciple the ordinary systems 
of mine ventilation are 
founded. In. the case of 
a deep mine, it is usual 
either to sink two shafts or 
to construct a bratticed 
single shaft. The underground passages are so con- 
nected as to form a series of uninterrupted channels 
'from one shaft to the other, see figure 36. As long as 
the air remains at the same temperature in both, no 
movement will take place ; but by placing a fire at the 
bottom of one shaft, the air column above becomes 
expanded, and rises; this upward movement is bal- 
anced by a corresponding downward current through 
the other shaft. By such means effective ventilation is 
maintained. 

Lyman's VentilatOP. — A principle exactly oppo- 
site to that of creating upward currents by means of 




Fig. 35. 

Opposite currents in a divided 
channel. 



VENTILATION. 



97 



heat has also been practically applied. This consists 
in causing a descending current by cooling the air 
above. Upon this principle Lyman's ventilator (figure 




Fig. 36. 
Upcast and downcast currents in a mine. 

37) is constructed. This device consists of a box 
containing ice (a) ; the bottom (5) is perforated, and 
a gutter and waste pipe (c) are arranged below, to 
catch the water from the melting ice ; a large flue (^d) 
conducts the cold descending air into the rooms ; an 



98 



DOMESTIC SCIENCE. 



upper box (e) usually made of wire, contains charcoal, 
which serves to purify the entering air and also to re- 
tard the melting of the ice.* 

Currents in Rooms. — Even within closed rooms, 
moving currents with consequent draughts are frequent. 
During cold weather the windows are considerably 
colder than the thicker walls, consequently the inside 

air in contact with the cold 
glass becomes chilled and 
falls ; while a warmed 
current from other parts 
of the room sets In to fill 
the space vacated by the 
descending cold air. A 
person sitting by a win- 
dow under such circum- 
stances would be entirely 
enveloped in the falling 
cloud of cold air, with 
great detriment to his 
health. To lessen this 
danger, builders now plan 
double windows consisting 
of an outer and an inner 
sash, with a few inches 
j..^ ^^ space between. The air 

Lyman's ventilator. within this space serves as 




*Youmanssays of this ventilator: "This arrangement on a 
small scale has been mounted on secretaries, to secure a cool and 
refreshing air while writing; over beds to cool the air while 
sleeping; and over cradles to furnish pnre air for sick chil- 
dren." 



VENTILATION. 99 

a non-conducting wall separating the outer cold at- 
mosphere from the warmer air of the room. By 
holding a candle flame near the windows, and alongside 
the walls, the presence of complicated currents within 
the room will be at once revealed. Most of the sim- 
plest methods of ventilation are associated with the 
means of warming the apartments; indeed the sub- 
jects of ventilation and warming are so closely related 
that to consider them independently of each other 
would be almost impossible. 

Fires as Aids to Ventilation. — A good fire in an 

open grate necessitates an ample chimney draught; the 
rising current within the flue exerts a powerful aspir- 
ating effect, which results in the ready removal of air 
from the room. A corresponding quantity of outer 
air must enter, to replace that which has been taken 
away. This incoming air causes a powerful current 
through the room toward the grate ; indeed, in the 
case of the wide open grates of olden times, the 
draught was so strong that our worthy ancestors 
found it necessary to provide specially constructed 
seats, called settles, with high, close backs, for use 
before their roaring fires. In comparison with these 
huge fire places, capable of admitting the Yule logs 
without difiiculty, the open grates of modern times 
seem very much contracted ; the space above the fire 
bars, — and this largely determines the aspirating 
power of the grate, — being now reduced to the small- 
est possible dimensions. Many forms of ventilator- 
stoves have of late appeared for sale. Such a stove is 
constructed with a double casing ; air enters below. 



100 



DOMESTIC SCIENCE. 



and after becoming warmed it escapes into the room 
through a perforated top. This subject of house 
warming will receive attention in a subsequent chapter ; 
(chap. 12). 

Chimneys and Double Flues. — The aspirating 

effect of a chimney increases in proportion to the 
energy of the fire ; though observation has proved 
that a decided draught is noticeable in chimneys even 
when no fire is in the grate. If a chimney be con- 
structed with a double flue, one division may be used 
specially as a ventilating shaft ; the air within it, being 
warmed through proximity to the heating flue, will 
rise with vigor. An objection to the use of double 

flues has been found in the 
fact that, if of improper 
construction, or if there be 
no adequate inlet for air to 
the apartment, they are apt 
I to permit downward cur- 
rents, and thus to draw in- 
to the room smoke from the 
fire flue. 

Flue Reg'isters. — The 

apertures that lead from the 
room into the flue are usu- 
ally guarded by adjustable 
registers, the commonest 
form of which consists of 
an iron grating and a mov- 
Fig. 38. able back, so arranged that 

Giiiis system of ventilating, the passage may be opened 




VENTILATION. 101 

or closed at pleasure. The efficiency of such a register 
may be greatly increased by attaching to the inside of 
the bars a flap of thin oil cloth or of oiled silk ; this 
will yield to pressure from the room toward the chim- 
ney, but the least impulse in the opposite direction 
will push the curtain into close contact with the inside 
of the register, thus preventing the entrance of back 
currents into the room. Perhaps the best contrivance 
of the kind is the Arnott valve, which consists of a 
movable door of metal, set in the chimney aperture, 
and so delicately adjusted as to yield to the slightest 
current toward the chimney, and to close firmly and 
easily when pressed in an opposite direction. 

Ventilation by Steam Wapming*. — For the 

ventilation of large buildings, many devices depending 
upon the expansion of air by warming have been pro- 
posed. A very efficient method is known as the OilUs 
system ; this, however, can be used only in steam- 
warmed buildings. As is shown in figure 38, a large 
shaft extends from the lowest floor upward through the 
roof. Up the center of this shaft a steam pipe is carried 
from the boiler A, In each room, two openings, one 
at the top and the other near the floor, communicate 
with the shaft ; these apertures are provided with 
registers and automatic valves. The heat of the steam 
pipe causes a powerful upward current, by which air 
is drawn from the rooms. Steam radiators R, for 
warming the rooms, are supplied on each floor. 

2. MECHANICAL AIDS TO VENTILATION. 

Currents from Fans. — Many forms of air -pro- 



102 



DOMESTIC SCIENCE. 




pellers have been proposed for purposes of ^ventilation. 
Most of them possess some merit, and some of them 

rank among the most 
efficient of ventilators. 
The exhaust fan (figure 
39) seems to be a fav- 
orite device. Dr. Mott 
speaking of the Black- 
burn fan, one of the 
most efficient kinds, 
states that a single 48 
inch fan, if made to 
run at the rate of 500 
to 600 revolutions per 
minute, will carry off 
30,000 cubic feet of 
air per minute. Large fans, for the ventilation of 
buildings are usually operated by steam or water 
power; electric dynamos however may be used 
as a source of j)Ower. For producing air currents in 
small apartments, small portable fans set on ornamented 
stands, and operated by primary currents from local 
electric batteries, are now in common use. Such fans 
may be operated on tables, and desks, and over sleep- 
ing couches. 

Revolving cotvls on chimney tops, if properly con- 
structed, serve to increase the aspirating effects of 
chimney flues. 

Pipes as Inlets for Air.— Thus far our attention 



Fig. 39. 
Exhaust fan. 



VENTILATION. 



103 



has been applied to methods for removing the foul air 
from rooms ; adequate means for introducing a supply 
of fresh air are also to be considered. Many common 
forms of inlets are objectionable because of the injur- 
ious draughts to which they give rise. In the ventila- 
tion of large buildings, pipes are often employed for 
conveying air to the interior ; these can be easily oper- 
ated with good results ; but in small dwellings, win- 
dows and transoms are usually relied upon for admit- 
ting air. Where inlet pipes are used, however, a great 
advantage is possessed in the ease with which the in- 
coming air may be 
warmed . The pipes may 
be passed through a heat- 
ing box connected with 
the furnace ; and if the 
air thus warmed be 
found deficient in mois- 
ture, evaporating pans 
of water may be placed 
in the course of the 
stream. 

Window Currents, 
Ordinary and Deflect- 
ed. — By opening the 
upper sash of a window, 

Fig. 40. ^^ 

Entering current of air deflected a strong entering CUr 

toward ceiling. ^.^^^^ j^^y ^^^ established. 

The cold air, however, will fall rapidly, without dif- 
fusing itself sufficiently throughout the room. If there 




104 



DOMESTIC SCIENCE. 




//'/' 



IS^ 



be a fire in the room, this current of cold air will con- 
tinue its course to the 
grate, and thus be 
speedily taken from the 
room, having served 
but little the purposes 
of ventilation. It has 
been proved to be ad- 
vantageous to place a 
board at an angle on 
the upper -part of the 
sash, so as to deflect 
the entering current to- 
ward the ceiling (see 
figure 40.) 

On the same prin- 
Fig. 41. ciple, the efficiency of 

Transom hinged so as to deflect air tvanSOms mSiy be greatly 
currents toward ceiling. . j i u 

increased by hinging 
them at the bottom, so that they may be set obliquely 
toward the ceiling, as in figure 41. 

Cuppents Between Window Sashes. — With or- 
dinary windows it is a good plan, and one that is 
widely practiced, to raise the lower sash, and place 
beneath it a strip of board from four to six inches 
wide and of length suflflcient to extend across the win- 
dow opening, see figure 4 2. This leaves a space be- 
tween the sashes, through which air will enter the 
room, the current being directed upward. Before 
falling, the fresh air will have been diffused. 



VENTILATION. 



105 




Fig. 42. 

Currents entering between window 

saslies. 



Diffusing" the In- 
coming" Aip. — It is 

possible to utilize win- 
dows both as inlet and 
outlet air passages. 
For breaking up the 
entering current so as 
to aid in its diffusion, 
sheets of finely perfor- 
ated metal may be in- 
serted in the upper sash 
in place of the ordi- 
nary glass panes, or 
gratings with inclined 
slots may be used to 
advantage. 



REVIEW. 

1. What is ventilation ? 

2. State the two general modes of purifying the air of 
rooms ? 

3. What powers are usually employed in changing the air of 
looms ? 

4. Show the value of temperature changes in moving the air 
of apartments. 

5. Illustrate the entering and out- going currents of a room 
with the door placed ajar. 

6. Fully explain the need of double passages in the case of a 
candle burning within a lamp chimney. 

7. How is this principle applied to the ventilation of mines ? 

8. How may descending currents of air be produced by 
cooling ? 

3 



106 DOMESTIC SCIENCE. 

9. Describe Lyman's ventilator. 

10. What is the effect of double windows in maintaining an 
equal temperature in rooms ? 

11. What is the value of fires in open grates in providing 
ventilation ? 

12. What do you know of the value of double flues in heating 
and ventilating rooms ? 

13. Explain the operation of the Arnott valve in ventilating 
flues. 

14. Explain the Gillis system of ventilation. 

15. Name the principal mechanical aids in ventilation. 

16. Explain the value of the exhaust fan in ventilating. 

17. State the essential features of a good inlet for air to a 
room. 

18. How may the incoming air be properly deflected upward ? 

19. Show the value of windows as inlets for air. 

20. Explain the use of transoms as inlets. 



SOME PROPERTIES OF HEAT. 107 

CHAPTER 9. 

SOME PROPERTIES OF HEAT, 

The close relation existing between the processes of 
ventilation and those of house warming has been 
already mentioned. Incidental reference has been 
made to some methods of domestic warming, but be- 
fore attempting any detailed consideration of the sub- 
ject, it will be well to turn attention to some of the 
simple principles by which the form of energy known 
as heat is controlled. 

Nature of Heat. — Heat is that force which, when 
operating upon the nerves of the living body, pro- 
duces the sensations of warmth and cold. The true 
nature of heat, as indeed of all other forms of force, 
is very imperfectly understood by mankind ; but it is 
a general belief among experimenters and thinking 
men, that heat in a body is the manifestation of 
motion among the particles. The plausibility of this 
view is strengthened by the fact that motion may be 
transformed into heat; and conversely, heat may be 
made to originate motion, with but little unaccounted 
loss of energy in either case. There is good reason for 
believing that as a body grows warm its particles are 
made to move, within certain limits, with increasing 
speed, and that at the same time they are driven farther 
apart, and thus the size of the body is increased. In 
the case of a fusible solid, iron for example, the 
temperature may be raised till the particles are so far 
separated that their cohesion is greatly diminished, and 



108 



DOMESTIC SCIENCE. 




the liquid state results. If the molten material be 
still more highly heated, the gaseous condition may be 
reached, the vapor of iron thus produced correspond- 
ing in physical state to steam. 

Expansion of Solids by Heat. — The general 

effect of heat when applied to 
bodies is to cause expansion. 
This is true of solids, liquids, 
and gases. Figure 43 illus- 
trates a common experiment 
upon this point. A ring and 
a ball of metal are provided ; 
they are of such relative sizes 
that the ball while cold will 
readily pass through the ring. 
By heating the ball, however, 
it becomes enlarged, and will 
no longer pass through the 
ring. The blacksmith applies a practical knowledge 
of this principle when he heats the tires of wheels 
before fitting them about the felloes; the iron, he 
knows, will contract in cooling and thus the tires will 
fit the more tightly. 

The Pyrometer. — The apparatus shown in figure 
44 serves to demonstrate very plainly the expansion of 
a solid by heat. A bar of metal is supported on two 
pillars, one end of the bar is firmly held by a screw ; 
the other end, which is free to move, rests lightly 
against a lever, and this is attached to a pointer which 
moves over a graduated arc. As the bar is heated by 
lamps placed beneath, it elongates and thus moves the 



Fig. 43. 
Ball enlarged by heat. 



SOME PROPERTIES OF HEAT. 109 

I 

index finger. An instrument of this kind is called a 
"pyrometer," the word meaning a measurer of heat 
or of fire. Pyrometers are used to measure very high 




Fig. 44. 
Pyrometer. 

temperatures ; such as the heat of a furnace. Ordi- 
nary thermometers would be destroyed by such great 
heat. 
Force Exerted by Expanding" Solids. — The 

force exerted by the expansion of solids through in- 
creasing temperature, is enormous. The iron rods 
and cables of which suspension bridges are made, 
move through considerable distances in the course of a 
season's range of temperature.* A difference of 81*^ 
F. between summer and winter temperatures is by no 
means uncommon ; yet such a change operating on a 
bar of wrought iron 10 inches long, would increase its 
length 1-200 inch ; this force is equivalent to a strain 
of 50 tons. It has been shown by careful trial, that 
a bar of iron measuring 1 square inch in cross -section, 
in being warmed from the freezing point to dull -red 

*0f the Brittania bridge an observer has said, "The pon- 
derous iron tubes writhe and twist like huge serpents under 
the varying influence of the solar heat. The span of the tube is 
depressed only a quarter of an inch by the heaviest train of cars, 
wh un lifts It two and a half inches." 



110 DOMESTIC SCIENCE. 

heat, will elongate about 6-1000 of its original length. 
The mechanical strain needed to stretch such a bar to 
this extent is about 90 tons. 

Effect of Temperatupe Chang-es on Pendu- 
lums. — Many practical illustrations of this principle 
may be observed in household operations. The 
pendulum rod of a clock elongates during warm 
weather and shortens during the cold season. Now 
the office of a clock pendulum is that of a regulator 
to the time piece ; by its swinging it controls the speed 
of the machinery. Observation proves that a long 
pendulum requires a greater time to vibrate than does 
a short one. In warm weather, therefore, the pendu- 
lum is apt to swing more slowly and thus cause the 
clock to fall behind time. In cold weather, on the 
other hand, the fast-moving pendulum causes the 
clock to run ahead of the true time. These irregu- 
larities may be in some degree corrected by raising 
or lowering the pendulum "bob" in accordance with the 
prevailing conditions of temperature. 

Some pendulums are so constructed as to partially 
regulate themselves; these are known as compensa- 
tion pendulums, the simplest of which is the grid- 
iron pendulum, sketched in figure 45. The pendulum 
rod consists of bars of two different metals, usually steel 
and brass, so arranged that the bars of one material 
can elongate only in a downward direction, they being 
fixed above ; while the other bars can expand only in 
an upward direction. Thus the upward and the 
downward expansion may be made to compensate 
each other. 



SOME PROPERTIES OF HEAT. 



Ill 



Another form of compensation pendulum is the 
mercurial hob pendulum, shown in figure 46. In this 
the lower part of the pendulum consists of a frame- 
work or box, within 
which are set a number 
of glass vessels, contain- 
ing mercury. Two such 
vessels are shown in the 
figure. As the pendu- 
lum rod elongates 
through increasing tem- 
perature, the mercury 
in the open vessels also 
expands and consequent- 
ly rises. These opposite 
expansions may neutral- 
ize each other's effect, 
and the "center of oscil- 
lation," which deter- 
mines the true length of 
the pendulum, may re- 
main unchanged. 

Expansion of 
Fluids by Heat. — Al- 
though we observe fewer 
illustrations of the ex- 




Fig, 45. 



Fig 46. 



Gridiron eonipen,- pan sion of liquids and Mercurial pen - 
sation pendulum. „ j xu • ia duluni bob. 

^ gases under the influence 

of heat, yet careful experiment will show that these 
bodies too, obey the general law. To show the ex- 
pansion of liquids under the influence of heat, take a 



112 



DOMESTIC SCIENCE. 




Fig. 47. 
Liquid expanding by heat. 



glass bulb attached to a stem, or a small glass flask as 
in figure 4 7, provided with a tight-fittiug cork 
through which passes an open tube; fill the vessel with 
water and gently warm. The liquid rises in the tube 

under the expansive in- 
fluence of the heat. 

To demonstrate the ex- 
pansion of gases, take a 
similar bulb or flask, 
empty and dry ; invert 
and place the stem in a 
vessel of water (see figure 
48). Grasp the bulb in 
the hand ; the warmth of 
the flesh will cause the air 
within to expand till it drives the water from the hollow 
stem and escapes in bubbles through the liquid in the 
tumbler. Such an apparatus is called an " air ther- 
mometer." Now remove the hand ; as the air cools it 

tends to resume its former 
dimensions ; but as a por- 
tion has escaped, a cor- 
responding quantity of 
water enters the bulb. 

Thermometers, — 
their Construction. — 

Upon the. expansion of 
liquids by heat depends 
the action of the ordinary 
thermometer. The word 

Fig. 48. 

Gases expanding when warmed, is derived from the Greek 




SOME PROPERTIES OF HEAT. 



113 



thermos, heat, and metron, measure, therefore a 
measurer of temperature. As commonly constructed, 
it consists of a bulb of thin glass with which a long 
hollow stem of fine caliber is continuous ; this is 
shown in figure 49. A quantity of liquid, (usually 
mercury or alcohol)* fills the bulb and extends some 
distance into the tube. The stem is 
hermetically sealed at the top, and the 
space above the fluid is a vacuum, the 
air having been removed therefrom be- 
fore the tube was sealed. A rise of 
temperature causes the liquid within the 
bulb to expand ; the only direction in 
which it is free to move is the upward 
one ; the liquid therefore rises. A cool- 
ing effect will result in a contraction of 
the liquid, and a consequent fall of its 
level within the tube. Such an instru- 
ment will reveal the fact of a difference 
of temperature ; but the degree of dif- 
ference cannot be determined till the 
thermometer is graduated. 

The Fahrenheit Scale. — The inventor of the in- 
strument was a German scientist, one Gabriel Fahren- 




Fig. 49. 
Thermometer 
bulb and stem. 



* Mercury (quicksilver) is usually employed in thermometers 
As this liquid freezes, however, at about'— 40° F. (i. e. 40 degrees 
below zero on the Fahrenheit scale) a mercury thermometer is 
useless for determining temperatures below that point. For low 
temperatures, thermometers containing alcohol are used. As 
alcohol boils at about 175° F. such a thermometer is unavailable 
forimeasuring temperatures higher than that. 



114 



DOMESTIC SCIENCE. 



heit, who lived in the early part of the last century. 
He set his thermometer in ice, and marked upon the 
tube the level at which the mercury stood : this degree 
of temperature he properly called the "freezing point." 
The instrument was then transferred to a bath of boil- 
ing water, and the level at which the mercury then 
stood was marked on the tube, 
and the temperature was named 
"boiling point." In a somewhat 
arbitrary manner, Fahrenheit then 
divided the space between the 
marks on the tube into 180 
sections; these he called ** de- 
grees." Fahrenheit knew that ice 
was not the coldest thing in ex- 
istence ; by mixing snow or 
cracked ice and salt he produced 
a much lower temperature ; so in 
a mixture of this kind he immersed 
the thermometer, and the level of 
the mercury was marked and called 
"zero." the space between that 
^ ■ . , point and the freezing point was 

Thermometer graduated t^ => ^ 

by the F. and the divided into 32 degrees. On the 
.sysems. Fahrenrenheit scale, (indicated by 

the abbreviation "F.") therefore, the freezing point is 
32° above 0°, and the boiling point is (180° + 32°=) 
212° above 0°. With a tube of uniform caliber, the 
graduations may be carried above and below these 
points. This scale of thermometric readings, though 



F. C. 


/so 




so 


//o 


\ \ 


IfO 


/oo 


- ■■ 


90 


: i 


1^ 


80 


: \ 




ZO 


70 


\ \ 


io 




: 


~10 


s-o 


\ : 


iro 






30 


: ■ 


o 

~10 


ZO 


j E 


/O 


: : 


- \ 


~ko 





: i 


/O 




: \ 




ZO 


\ \ 


CO 


( 


i 


) 



Fisr. 50. 



SOME PROPERTfES OF HEAT. 115 

very arbitrary in its nature, is the one most generally 
used among English speaking nations ; though for 
scientific and technical purposes another system has 
been adopted. 

The Celsius op Centig'rade Scale. — A Swedish 

scientist named Celsius, proposed to call the freezing 
point 0°, and the boiling point 100°, the space on the 
thermometer stem between the points thus indicated 
being divided into 100 equal parts; and the gradua- 
tion being continued both above and below these fixed 
points. The Celsius graduation is sometimes called 
the centigrade scale; it is indicated by the ab- 
breviation "C.*' Figure 50 shows a thermometer 
of simple construction, with scales attached after both 
the Fahrenheit and the Celsius (or centigrade) 
systems.* 

Relation Between the Two Scales. — The heat 

needed to raise a quantity of water from the freezing 
point to the boiling temperature will cause the mercury 
in a thermometer graduated after the Fahrenheit sys- 
tem to rise from 32° to 212°, or through a space of 180 
degrees ; and the same heat would raise the mercury 
in a Celsius thermometer from 0° to 100°, or through 
a space of 100 degrees. It will be seen then that: 



*ABOtlier thermometer scale is that devised by Reaumur, a 
French philosopher. On the Reaumur scale the freezing point is 
called 0°, and the boiling point 80.° Therefore 80 Reaumur degrees 
correspond to 100 Centigrade degrees, and to 180 Fahrenheit de- 
grees; and 80° R. = 100° C, = 212° F., that is, the boiling point of 
water. In the same way, 0° R. =0° C. = 32° F., that is, the freezing 
point. 



116 DOMESTIC SCIENCE. 

180 F. degrees correspond to 100 C. degrees. 

Then 9 F. '' " " 5 C. '* 

1 F. degree corresponds " Y9 C. degree. 
And 1 C. " " " VsF. 

Now, although as shown above, 180 of the Fahren- 
heit degrees correspond to 100 of the Celsius degrees, 
it does nut follow that the 180th degree above 0° 
F. should correspond to the 100th degree above 0° C, 
because the of the Celsius scale marks the freezing 
point, while the of the Fahrenheit scale is 32 Fahren- 
heit degrees below the freezing point. An allowance 
for this must be made in transforming the readings 
of one scale into terms ot the other. The truth of the 
following formulae will be seen without difficulty by 
the thoughtful student : 

F. = 75 C. + 32. 
C. = V9 (F.— 32). 

Utility of the Thermometer. — The thermome- 
ter is an instrument of great utility, and it certainly 
deserves a more extended service than is commonly 
allowed it in domestic operations. We are apt to 
place too much reliance in the indications of our 
organs of sense as to temperature, and these indica- 
tions are often deceptive.* 

*The old-time demonstration will illustrate the point. Provide 
three bowls or basins of medium size; into the middle one put 
water of or lu.aiv temperature, say about 65 degrees F, ; into one 
of the remaining vessels put some ice water; within the third place 
water as hot as can be borne without injury when in contact with 



SOME PROPERTIES OF HEAT. 



11 



Many cheap thermometers are inaccurately gradu- 
ated ; their error, however, seldom exceeds 2°. For 
domestic purposes, a thermometer possessing the fol- 
lowing charac- 
teristics will be 
found most gen- 
erally useful : 

(1) The grad- 
uation markings 
should be on the 
glass stem rather 
than upon an at- 
tached scale. 

(2) If set in 
a frame the tube 
should be readily 
removable that it 
may be used when 
so needed, to de- 
termine the temperature of liquids. 

(3) The graduations should extend at least from 
0° to 212° F. 

The Dial-face Thermometer. — Figure 5i is an 

illustration of a thermometer of recent production now 




Fig. 51. 
Dial-face thermometer. 



the flesh. Now immerse one hand in the hot liquid, the other in 
the ice water; take notice of the sensations, then plunge both 
hands into tlie bowl of water at ordinary temperature. To the 
hand that came from the hot water this seems unendurably cold; 
to the hand just taken from the ice water, the contents of the mid- 
dle bowl seem to be intensely hot. Neither of these sensations 
indicates the truth. 



118 



DOMESTIC SCIENCE. 



growing in use. The changes in temperature are 
indicated by the movements of an indicating finger over 
a dial face ou which are marked in bold figures the de- 
grees. The advantage of such an 
instrument is that its indications 
can be read from a considerable dis- 
tance ; whereas, in using the mer- 
curial thermometer the observer must 
stand very near the instrument; thus 
influencing the reading by the warmth 
of his own body. The essential in- 
ternal parts of the dial -face thermom- 
eter are shown in figure 52. A 
curved bar of metal, (or better, a 
compound bar of two metals) A B is 
firmly held at or near one end A. As 
the bar contracts and expands under 
the influence of changing temperature, the free end 
B moves, and this force being communicated through 
the rod C to the semi- circular piece D, turns the axis 
F, around which passes a silken thread E. To F as 
an axle is attached the indicating finger, which moves 
in front of the graduated face. Such an instrument 
is graduated to correspond with standard mercurial 
thermometers. 




Fig. 52. 
Essential parts of 
the dial -face ther- 
mometer. 



REVIEW. 

1. Define heat. 

2. What is the general effectof heat on matter ? 

3. Describe demonstrations of the expansive effect of heat 
on solids. 



SOME PROPERTIES OF HEAT. 119 

4. Give illustrations of the great force exerted by expanding 
solids. 

5. What is the use of a pendulum in a clock ? 

6. Explain the effect of varying temperature on the regu- 
larity of the clock's running. 

7. Explain the gridiron compensation pendulum. 

8. Explain the mercurial-bob pendulum. 

9. Describe experiments showing the expansion of liquids 
by heat. 

10. Illustrate the expansion of gases by heat. 

11. What is a thermometer ? 

12. Describe the mercurial thermometer. 

13. Explain its action. 

14. Which are the principal scales, according to which ther- 
mometers are graduated ? 

15. How are the fixed points of the scale determined ? 

16. Show the relation between the Fahrenheit and the Cen- 
tigrade scales. 

17. Deduce formula for transforming the readings of each of 
these scales into those of the other scale. 



120 



DOMESTIC SCIENCE. 



CHAPTER 10. 



COMMUNICATION OF HEAT ; LATENT AND SPECIFIC HEAT. 

Conduction of Heat. — if a bar of iron be set 
with one end in a fire, after a very short time the 
other end will have become hot. It is plain that in 
this case the heat must have come from the fire : it 
must have been communicated along the line of par- 
ticles from one end of the bar to the other. To be 
more accurate in expression, we should say the heat 
has been conducted along the iron : in consequence of 
the property here shown the metal is said to be a con- 
ductor of heat, and this process of heat-communication 
is known as conduction. 

An impressive illustration of this effect may be pro- 




Fig. 53. 
Conduction of heat in a bar of metal. 

duced as follows : — Provide a thick iron or copper 
wire, about a foot long (see figure 53), by means of 
wax attach to the bar at equal distances a number of 
marbles or small bullets. Insert one end of the bar in 
a flame : one by one the balls drop as the wax 
becomes softened, showing by their successive falls 
the invasion of the particles by the heat. 



COMMUNICATION OF HEAT. 



121 



The ConductometeP. — An apparatus designed to 
demonstrate the relative conductivity of different 

metals is shown in figure 54, 
it consists of a metallic box, 
carrying a number of rods of 
different substances. The 
free ends of the rods are 
first covered with wax ; the 
box is then filled with hot 
water, and the order in 
which the wax on each rod liquifies is noted. 

Conductivity of some Solids.— The common 

metals and alloys are arranged in the following order 
with respect to their conducting powers : 




Fig. 54 
Conductometer. 



(1) silver; 

(2) copper; 

(3) gold; 

(4) brass; 

(5) tin; 



(6) iron; 

(7) lead; 

(8) platinum; 

(9) German silver; 

(10) bismuth. 



To these may be added several common substances 
other than metals, arranged on the same plan : 



(11) marble; 

(12) porcelain; 

(13) clay; 

(14) woods; 

(15) fats; 

(16) snow; 



(17) silk; 

(18) charcoal; 

(19) cotton; 

(20) lampblack; 

(21) fur.* 



*Our most efficient fabrics for clothing are poor conductors of 
heat. A coat of fur or of woven wool, if wrapped about a living 
being will retain the bodily heat: if wrapped around a block of 
ice the same garment keeps the ice cold. In the one case the 
wrapping prevents the escape of heat from the warmer body to 
the cooler air: in the other it guards the ice against access of 
warmth. 



122 



DOMESTIC SCIENCE. 




Fig. 55. 

Convection of heat in a body 

of liquid. 



Convection of Heat in Liquids. — Most liquids 

are poor conductors of heat. 
This statement may seem 
strange when we think of 
the fact that heat seems to 
be uniformly distributed 
throughout liquid masses. 
Such distribution of heat is 
effected by other means 
than by conduction as above 
described. When liquid 
particles are heated they 
become specifically light, 
and consequently they 
rise, thus making room 
for colder particles, which 
in turn become warmed 
and rise. The course of the 
rising currents of warm 
water and the descending 
streams of cold may be 
seen by warming a flask 
or beaker containing wa- 
ter, to which a small quan- 
tity of sawdust or other 
finely divided, opaque 
matter has been added ; 

Fig 56. ' 

injibiiity of liquids to conduct (see figure 55.) Such a 

heat in a dowmvard direction. ^ode of diffusing heat by 

the successive warming of separate particles, is known 
as convection. 




COMMUNICATION OF HEAT. 123 

Poop Conductivity of Water. — if water were a 

good conductor of heat it would transmit heat as well in 
a downward as in an upward direction. The inabilitj'^ 
of the liquid to do this may be thus shown : A funnel 
(figure 56) with a wide throat is fitted with an "air 
thermometer" passing through its neck and dipping 
into a vessel of water below.* Water is poured into 
the funnel till the thermometer bulb is covered ; a 
little ether is then poured upon the water and ignited. 
Though the flame be within half an inch of the bulb, 
so little heat is conducted downward as scarcely to 
cause an expansion within the bulb. 

Radiation of Heat. — There is a third method 
by which heat is diffused, as may be shown by 
holding the hand in front of a fire. The flesh soon 
becomes warmed; not by conduction, for between 
the hand and the fire there is no material connection, 
except the air, and air like all gases, possesses but 
slight conductivity ; neither is the hand warmed by 
convection, for warm convection currents are ascend- 
ing ones. It is plain that the heat must have pene- 
trated the intervening air ; must have traveled from 
the fire to the flesh. Such mode of heat communica- 
tion is known as radiation^ and the heat so trans- 
mitted is called radiant heat. Radiant heat passes 
outward from its source, along straight lines in all 
directions ; the heat rays fall upon objects in their 
course and warm them, without, however, greatly rais- 
ing the temperature of the intervening air. Radiant heat 

*See figure 48 as an illustration of the air thermometer." 



124 DOMESTIC SCIENCE. 

may be transmitted in a vacuum, thus proving its in- 
dependence of air as a medium of conveyance. The 
laws of its motion are similar to those of light; it 
comes to us from the sun associated with light, both 
traveling at <he rate of 185,000 miles per second. 
The intensity of radiant heat diminishes as the square 
of the distance from its source increases ; therefore a 
person sitting within two feet of a fire would receive 
four times as much radiant heat as would fall upon a 
second person situated four feet from the fire. 

HIDDhN HEAT : LATENT AND SPECIFIC. 

Nature of Latent Heat. — In speaking of the 
measurement of heat, we have thus far dealt only 
with thermometric indications ; yet there are many 
operations in the course of which heat changes are 
not revealed by the thermometer. Thus a vessel con- 
taining ice at the freezing temperature may be exposed 
to heat, but until the ice has become thoroughly liqui- 
fied the thermometer would indicate no rise. The 
energy has not been lost however ;^ it has been ex- 
pended in separating the ice particles, and in over- 
coming the cohesion between them so as to produce 
the liquid state ; and this energy will be again 
freed as heat when the liquid returns to the solid con- 
dition.* The heat so escaping thermometric measure- 
ment is known as latent heat. 



* Though paradoxical, it is true that the freezing process is 
associated with the liberation of heat, and is therefore in one 
sense a warming process. In passing from the liquid to the solid 



COMMUNICATION OF HEAT. 125 

Latent Heat of Melting* Ice and of Boiling* 

Water. — The heat thus rendered latent in the melting 
of ice is about 80 times that required to warm the 
same amount of water 1° C. Heat is also rendered 
latent in changing substances from the liquid to the 
gaseous state. In the boiling of water much heat is 
absorbed, the steam being no warmer according to 
the thermometer than was the water at the instant of 
its vaporization. Experiment shows that to vaporize 
a given quantity of water at the boiling temperature 
requires about 537 times as much heat as is needed to 
raise that same quantity of water through a range of 
1° C. 

Nature of Specific Heat. — Under all circum- 
stances, water appears comparatively sluggish in 
responding to the influences of heat. The amount of 
heat that would raise a pound of water 1° in temper- 
ature, would warm 30 lbs, of quicksilver through the 
same range. We perceive then that different sub- 
stances possess varying capacities for heat. If to 
warm a quantity of water through a given range of 
temperature requires 30 times as much heat as would 
serve to similarly warm an equal amount of mercury, 
then in cooling, the water would give out 30 times as 
much heat as would the mercury. The relative capac- 



state, water gives out all of the heat acquired by it and rendered 
latent in melting. This principle is often made use of to prevent 
the freezing of vegetables and fruits during cold weather. Open 
vessels of water placed in proximity to such perishable articles 
in a closed room, will liberate sutEcient heat to warm the air of 
the room through a range of several degrees. 



126 



DOMESTIC SCIENCE. 



ity of substances for holding and retaining heat is 
known as their specific heat. 

An instructive demonstration of specific heat may 
be made thus (figure 57) : Procure a number of smaU 
balls of equal weight, one each of iron, copper, silver, 
tin, lead, and bismuth. Heat all to the same temper- 
ature by immersing them in a bath of hot oil ; then 
place them on a cake of paraflSn or of bees' wax. The 
iron soon melts its way through the wax ; then follow 
in order the copper, the silver, the lead, and the bis- 
muth. Some of the metals 
therefore are much better 
absorbents of heat than 
are others. 

Relative Specific 

Heats. — Considering 
water as the standard, 

the specific heat of several common substances may be 

expressed as follows : 




Fig. 57. 
Demonstration of specific heat 



♦Water 

Air 

Oxygen 

Sulphur 

Iron 

Copper 

Silver 

Tin 

Mercury 

Lead 

Bismuth 

Alcohol 

Ether 



100 

23.75 

21.75 

20.26 

11.38 

9.52 

5.70 

5.62 

3.33 

3.U 

3.08 

5.05 

5.46 



*"It is because water is capable of receiving so much heat that 
it is better adapted than any other substance to quench thirst. A 
small quantity of it will go much farther in absorbing the feverish 



COMMUNICATION OP HEAT. 127 

Good Results fpom the Laws of Latent and 

Specific Heat. — The beneficial effects resulting from 
the operation of these laws of latent and specific heat 
are of the highest order. Suppose for a moment that 
the principle of latent heat did not exist. As spring 
time approached, the vast masses of ice and snow of 
lakes, rivers, and mountains would become warmed 
to the temperature of 32° F., the melting and freezing 
point of water ; and the least further rise would 
result in an immediate mighty bursting of the bonds 
of frost ; the ice and snow would become almost in- 
stantaneously liquified, and wide-spread destruction 
would be inevitable. But the All -seeing One has 
wisely decreed that much heat shall be required to 
change the physical state of matter ; such changes 
must then of necessity be gradual ; and in orderly 
march, with the precision of prisoners under full con- 
trol, these frost-bound particles return to their condi- 
tion of liquid liberty. So, too, the advances of winter 
are restrained and the severity of the season is tem- 
pered by reason of the great amount of latent heat 
escaping from freezing water. But for the operation 
of this principle, a fall of temperature only one degree 
below the freezing point, would result in the instan- 
taneous formation of ice on a stupendous scale. Try 
to think of the possible results, if as soon as the boil- 

heat of the mouth and throat than an equal amount of any other 
liquid. When swallowed and taken into the stomach, or when 
poured over the inflamed skin, it is the most grateful and cooling 
of all substances. For the same reason, a bottle of hot water 
will keep the feet warm much longer than a hot stone or block." — 
Dr. Youmans. 



128 DOMESTIC SCIENCE. 

ing point were reached, water was instantly converted 
into steam. Such a prodigious expansion would be 
followed by demonstrations of explosive violence, such 
as man cannot conceive of. Were it not for its high 
specific capacity for heat, water would respond with 
alarming readiness to the slightest changes of tempera- 
ture ; and the result could not be other than destruc- 
tive. But such dire calamities are prevented through 
the operation of the laws of nature, which are the 
laws of God. These stupendous forces are under per- 
fect control ; the Mighty One holds them in His 
power. 



REVIEW. 

1. How would you demonstrate the conduction of heat in a 
bar of metal ? 

2. Describe a conductometer. 

3. Give the order of conductivity of several common sub- 
stances. 

4. What do you know of liquids as conductors of heat? 

5. How would you demonstrate the inability of liquids to 
conduct heat downward ? 

6. Explain convection of heat in a liquid. 

7. Explain radiation of heat. 

8. Define latent heat. 

9. In what common processes is heat rendered latent ? 

10. State the amount of heat rendered latent in the melting of 
ice. 

11. In the vaporization of water. 

12. What is specific heat ? 

13. Describe a demonstration of the difference of specific heat 
in the case of several substances . 



COMMUNICATION OF HEAT. 129 

14. Give illustrations of the relative specific heat of different 
substances. 

15. Explain the great benefits resulting from the operation of 
the laws of latent and specific heat. 



130 DOMESTIC SCIENCE. 



CHAPTER 11. 

PRODUCTION OF HEAT *, FUELS AND FLAME. 

Aptificial Production of Heat.— The earth is 

warmed by the heat rays that come to it from the sun. 
That brilliant orb has been constituted by the Creator 
as the source of warmth, of light, and of chemical 
energy for our globe. During the cold season, when 
we receive less directly these energizing rays, and dur- 
ing the night, when the hemisphere on which we live 
is turned away from the glowing sun, and for special 
purposes at other times, it is necessary to provide for 
the artificial production of heat. The common methods 
of accomplishing this depend upon the chemical energy 
of combustion ; and when employed for such purposes 
combustible substances are known as fuels. 

A Candle. — To aid us in comprehending the chem- 
ical processes attending the burning of fuel, let us 
examine a small flame ; that of a candle will answer 
our purpose well ; but first, a word as to the candle 
itself. A candle consists of a solid cylinder of wax or 
tallow, or some such easily fusible and combustible 
material ; this is the fuel. In the middle of this cyl- 
inder a wick is placed ; this serves by its porous nature 
to convey the melted wax from the little cup at the 
top of the cylinder to the region of the flame. 

Products of Combustion of Candle. — In the 

burning process a union occurs between the carbon 



PRODUCTION OF HEAT. 



131 




[Fig. 58. 

Moisture formed by the candle 
flame condensing on a cold 
■ tumbler. 



and the hydrogen of the fuel, and the oxygen of the 
air. Hydrogen in burning with oxygen produces water ; 

carbon in so combining 
forms carbon dioxide. 
Hold over a candle flame 
a dry, cold goblet (figure 
58) ; water from the flame 
condenses on the inside of 
the glass. A similar thing 
occurs when a cold lamp 
chimney is placed in posi- 
tion over the freshly 
lighted wick. Soon, how- 
ever, goblet and lamp 
chimney become so warm 
as not to allow the deposition of water. 

Now arrange an apparatus as shown in figure 59. 
The gases rising from the burning candle are drawn 
through the bottle, in which is a quantity of clear 
lime water. This lime water soon becomes turbid 
from the formation within it of insoluble lime carbon- 
ate. This, it will be remembered from previous ex- 
periments, (see page 4 7) is a proof of the presence of 
carbon dioxide. 

Flame is Burning' Gas. — The flame of the candle 
is due to the combustion of gaseous matters. Fuels 
containing large quantities of volatile combustible 
matters burn with large flames ; such is the case with 
resinous woods, soft coals, tar, pitch, oils, and the 
like; while fuels consisting mostly of fixed carbon, 
such as charcoal, coke, and anthracite coal, burn with a 



132 



DOMESTIC SCIENCE. 



steady glow, but with little flame. Indeed, flame may 
be regarded in all cases as burning gas. To demon - 





Fig. 59. 
Gases rising from a candle flame being drawn through lime water. 

strate this fact, let us return once more to our candle. 

When it is burning brightly, blow it out by a sudden 

puff ; a stream of vapor 
is now seen rising from 
the wick ; this consists 
of the volatile part of the 
wax, which had been 
carried to the region of 
the flame, but now that 
the candle is extinguished 
it cannot burn, therefore 




Fig. 60. 
Combustible vapors of volatil- 
ized wax. 



it escapes. Now apply a light to this rising column 



PRODUCTION OF HEAT. 



133 



of vapor; the flame runs along the line and re-ignites 
the wick. 

That this combustible vapor is produced through the 
action of the heat on the wax, may be proved by 
warming a quantity of wax in a glass tube provided 
with an escape jet ; vapor rises and may be burned as 
it issues from the jet (figure 60). 





Fig. 61.. 
Showing that the candle flame 
is hollow. 



Fig. 62. 
Match head in center of flame 
remaining unburned. 



Structure of Flame. — The hollow nature of the 
flame may be shown by placing a splinter of wood 

across the flame, as in figure 
61. A charring action will 
occur where the outer shell 
of flame touches the wood ; 
but between these points the 
wood is unscorched. By 
deft action a match head 
„. -, may be introduced into the 

Fig. 63. -^ 

Showing that flame is hollow, flame center, and there held 
un lighted, though the heat may be sufficient to melt 
the ignition material (see figure 6 2). A strip of paper 
may be depressed upon the flame, as in figure 63. On 




134 DOMESTIC SCIENCE. 

being removed a blackened ring, inclosing an un- 
scorched center will be seen. 

Fuels. — The processes operating in and about the 
larger flames may be thus understood from the study 
of a burning candle. The hydrogen and the carbou 
of burning wood and coal unite with the oxygen of 
the air, and in so doing they evolve heat. Fuels are 
efficient in proportion to the amount of hydrogen and 
carbon they contain. All solid fuels, however, con- 
tain a considerable quantity of incombustible matter ; 
the fixed portions of which remain after the burning 
in the form of ash. 

Moisture in Fuels. — Another cause of the diminu- 
tion in the heating value of fuels lies in the amount of 
water contained by them. We all know that green 
woods, rich in sap, are far less efiicient fuels than are 
dry woods. Water in fuels lowers the percentage of 
available oxygen and carbon ; its presence retards the 
combustive process, by absorbing much heat as the 
burning proceeds ; and when the boiling temperature 
is reached, the water is converted into steam, and thus 
a large amount of heat is rendered latent, and is car- 
ried off by the escaping vapor. 

Heating" Power of Fuels. — The calorific or heat- 
ing power of fuels depends upon the amount of oxy- 
gen with which they unite in the course of combustion. 
Thus, 1 lb. of hydrogen while burning will combine with 
8 lbs. of oxygen ; while 1 lb. of carbon unites with 2 Ys 
lbs. of oxygen. Hydrogen in burning produces over 
three times as much heat as does the same weight of 
carbou. The practical efficiency of hydrogen as a fuel 



PRODUCTION OF HEAT. 135 

is lowered, however, by the fact that the water pro- 
duced by its combustion absorbs and renders latent a 
large proportion of the heat. The carbon dioxide 
resulting from the burning of carbon, having appar- 
ently little capacity for heat, and undergoing no 
change of state, absorbs much less of the heat of com- 
bustion. For practical purposes, therefore, the pro- 
portion of fixed carbon in fuels largely determines their 
relative efficiency. 

Wood as Fuel is still in extensive use, where it is 
plentiful. Ordinarily, wood contains a large amount 
of water.* It is usually allowed to become air- dried 
before being burned ; by this its efficiency is greatly 
increased. Soft woods burn quickly, and give out a 
comparatively intense heat in very short time ; but they 
burn out much more rapidly than do hard woods. 
Common woods may be ranged in the following order 
with respect to their heating values, the poorer kinds 
being named first : — white pine, poplar, soft maple, 
cherry, cedar, elm, hard maple, yellow oak, wal- 
nut, beech, apple, scrub oak, white ash, white oak, 
hickory. 

Coal exists in many forms, and of widely varying 
degrees of efficiency as fuel. There is much evidence 

*" Suppose that 100 pounds of wood contain 30 of water, they 
have then but 70 of true combustive material. When burned, 1 
pound of the wood will be expended in raising the temperature 
of the water to the boiling point, and 6 more in converting it into 
vapor; making a loss of 7 pounds of real wood or one-tenth of 
the combustive force. Besides this dead loss of 10 per cent, of 
fuel the water present is an annoyance by hindering free and 
rapid combustion." 

YOUMANS. 



136 DOMESTIC SCIENCE. 

to support the view that mineral coal is but trans- 
formed vegetable matter. The remains of many plants 
are found in mines ; the microscope reveals, even in 
the ash of the hardest coal, a cellular structure similar 
to that known to exist in plants ; a substance verj'^ 
similar to coal has been artificially made through the 
operation of heat and pressure upon sawdust and 
other finely divided vegetable matter. Coals are 
usually classified according to the degree of metamor- 
phism to which they have been subjected, as shown by 
the varying amounts of volatile matter which they still 
contain. The chief varieties are lignite, cannel coal, 
bituminous coal, semi -bituminous coal, and anthra- 
cite.* 

LigTlite, often called brotvn coal, plainly shows the 
woody structure. It is soft and lusterless, and so dif- 
ferent in appearance from the common forms of coal, 
that at first sight one scarcely considers it as belonging 
to the same family. A typical sample from Saxony 
was analyzed by the writer and found to consist of : 

Moisture, - - - - - 8.24 per cent. 

Volatile combustible matter, - 49.96 " 

Fixed carbon, . . . . 38.8 1 " 

Ash, 3.45 

Cannel Coal, which in some places is known as 
parrot coal, is usually grayish black in color, dense 
and lusterless. When broken it shows a conchoidal 
or shell shaped fracture. It contains a tolerably large 
percentage of volatile matter, and is consequently well 
adapted for the manufacture of gas ; in England it is 

*See the author's " First Book of Nature," chapter 4B. 



PRODUCTION OF HEAT. 



137 



known as gas coal. The name cannel is due to a prac- 
tice still followed in Scotland, of using thin pieces of 
the coal in place of candles (Scottish pronunciation, 
cannels). A good sample of cannel coal from Virginia 
yielded to the author's analysis : 



Moisture 

Volatile combustible matter 

Fixed carbon 

Ash - . - - 



0.243 per cent. 
60.818 
S5.135 " 

3.882 



Bituminous Coal contains from 40 to 50 per cent, 
volatile matter. This constitutes the commonest class 
of coals. It is a black, lustrous, friable solid, and 
burns with a large flame. Varieties of this coal that 
are especially rich in volatile substances are described 
SLsfat bituminous coals. 

The following tables give the composition, accord- 
ing to the author's analyses, of several kinds of bitu- 
minous coal as sold in Utah : 





(-1 

o - 
OS 


O o 




m Pleas - 

alley, 

ah. 


o 






2i 

■3^ 


al fro 
ant V 

Ut 


•3 ^ 




o ' 


o CO 


o 


o 


o 




o 


Q 


o 


o 


D 


Moisture 


8.11 


7.82 


1.21 


4.56 


8.71 


V^olatile combustible matter 


4'2.75 


43.57 


42.81 


39.05 


33.16 


Fixed carbon 


46.44 


47.28 


52.35 


54.68 


56.88 


Ash 


2.68 


1.30 


3.61 


1.70 


1.24 



Coal containing large amounts, say near 50 per cent, 
of volatile ingredients softens much in burning. Such 
kinds are popularly called coking coals. 

Semi-bituminous Coal contains from 15 to 20 

per cent, volatile matters. It is richer in hydrogen 



138 DOMESTIC SCIBI*CE. 

than is anthracite, and it contains more fixed carbon than 
does bituminous coal proper. Owing to its ready 
inflammability and the comparatively little smoke at- 
tending its burning, it is in high favor as a fuel for 
engines and boiler fires, and is often called steam coal. 

Anthracite is a hard, brittle, and highly lustrous 
coal. In structure it is very dense, and in breaking it 
shows a conchoidal fracture. It may contain upwards 
of 90 per cent, fixed carbon, leaving therefore small 
room for volatile ingredients. 

A specimen of anthracite coal from Crested Butte, 
Colorado, gave in the author's analysis the following 
composition : 

Moisture .... o.59 per cent. 

Volatile combustible matter - 6.48 " 

Fixed carbon .... 90.04 " 

Ash ..... 2.43 " 

In burning, anthracite coal evolves great heat, but 
produces little or no flame. Coke formed from an- 
thracite differs in appearance but slightly from the 
coal itself. In different sections of our own country, 
anthracite is popularly known as glance coal, stove 
coal, and hard coal ; in Ireland it is commonly called 
Kilkenny coal; in Scotland it is called from its flame - 
less burning blind coal. 

The varieties of coal here named are but the chief 
or typical kinds. Numerous others are known, differ- 
ing in degree from the ones mentioned. Besides the 
natural fuels, certain forms of artificially prepared car- 
bon are also used ; the chief of these are charcoal and 
coke. 



PRODUCTION OF HEAT. 139 

Charcoal is produced from wood by distilling off 
the volatile matters ; it remains after the process as a 
black, brittle solid, containing all the fixed carbon and 
ash of the wood. Being very porous, charcoal readily 
absorbs moisture. 

The common method of preparing charcoal consists 
in piling the wood around a central flue ; covering the 
heap with earth, and kindling a fire at the bottom of 
the flue. Some of the wood is burned and thus pro- 
duces sufficient heat to distill the volatile matters from 
the remainder. The energy of the combustion is con- 
trolled by regulating the admission of air to the heap. 
A better method consists in using dome -shaped kilns 
specially constructed for the purpose. Any method is 
wasteful if it allows the escape and loss of the volatile 
ingredients; in the best processes the volatile matters 
are collected and used. Charcoal has many uses beside 
those of fuel ; some of these will be subsequently 
referred to. 

Coke results from the distillation of coal; it con- 
tains therefore all the fixed carbon, and the ash of the 
coal. It is made in large quantities as a by-product in 
the preparation of coal gas. Coke is a porous, friable 
solid, grayish in color, and of medium luster. It is 
largely used as a fuel in metallurgical operations. 
Being devoid of volatile ingredients, coke burns with 
a steady, flameless glow, evolving much heat. 

Coal Gas is a very convenient and an efficient arti- 
ficial fuel. However, the cost of its production and 
distribution prevents its use as a heating medium be- 
coming general. As furnished by its manufacturers, 



140 DOMESTIC SCIENCE. 

coal gas may be regarded as the partly purified volatile 
matter of coal. Its use is attended by considerable 
danger, owing to its poisonous properties and the ex- 
plosive nature of mixtures of gas and air. Coal gas 
is in more general use as an illuminant, though gas 
stoves for heating purposes are in frequent service. 

Gasoline as Fuel. — Vapor stoves for the burning 
of volatile oils are now in common use. They depend 
for efficacy upon the burning of the light vapors 
of petroleum, such as benzine and gasoline, 
between which substances, as found in the market, 
there is very little difference other than that of the 
prices charged for them. 

Tindep-box and Sulphup Matches. — The mode 

of starting fire is an interesting subject for study. In 
very early times, it is said our ancestors developed 
fire by forcibly rubbing together pieces of dry wood ; 
this method was laborious and its results uncertain, 
though it is still employed among savage tribes. An 
advance was made in the use of flint and steel with 
which to produce a spark, and tinder to be inflamed 
thereby. In the early part of the present century the 
tinder-box was a household necessity. Sulphur 
matches^ consisting of a globule of sulphur on the end of 
a splinter of dry wood, were used in connection with 
the tindor, the low igniting point of sulphur making 
it possible to readily procure a flame from the smolder- 
ing tinder. 

Phosphorus Matches.— The matches of the 
present day depend for their inflammability upon the 
presence of phosphorus. Common matches are made 



PRODUCTION OF HEAT. 141 

by dipping the bits of wood in melted sulphur, and 
afterwards in a paste of phosphorus, potassium 
nitrate (nitre), and glue. Slight friction inflames the 
phosphorus, this ignites the sulphur, while the nitre 
decomposes and furnishes oxygen to aid the combus- 
tion. The glue forms a hard coating impermeable to 
air, so that the phosphorus within the match head is 
protected from oxidation till by friction the outer 
layers are worn away. In the crackling or explosive 
matches, potassium chlorate is used in place of nitre ; 
such matches burn quickly. If a colored match -head 
be desired, a pigment, usually vermillion, red lead, or 
Prussian blue, is stirred into the paste. 

Safety Matches. — Many serious results have 
followed the accidental ignition of matches ; and as a 
partial safeguard safety matches were invented, though 
their use has not become general. Safety matches are 
capped with a mixture of potassium chlorate, anti- 
mony sulphide, and glue ; they ignite only when 
rubbed on a prepared plate containing red phosphorus 
and fine sand or powdered glass. The red or amorphous 
phosphorus is far less dangerous in use than is the 
ordinary waxy phosphorus. 



REVIEW. 

1. What is fuel ? 

2. Describe the parts of a candle and the changes going on 
as it burns. 

3. Prove that water is a product of ordinary combustion. 

4. Show that carbon dioxide is produced by a burning candle. 



142 DOMESTIC SCIENCE. 

5. Explain the production of water and carbon dioxide in 
ordinary combustion. 

6. What is flame ? 

7. Show that the flame of a candle results from the burning 
of combustible vapors. 

8. Describe three demonstrations of the hollow form of flame. 

9. Explain the effect of water in fuels. 

10. What do you know of wood as a fuel ? 

11. What evidence have you that coal is probably formed from 
vegetable matter ? 

12. Name the principal kinds of coal. 

13. What do you know of lignite ? 

14. Of cannel coal ? 

15. Of bituminous coal ? 

16. Of semi-bituminous coal ? 

17. Of anthracite? 

18. How is charcoal produced? 

19. What do you know about coke? 

20. Discuss coal gas and natural gas as fuels. 

21. Explain the operation of the old time tinder-box, flint and 
steel, in producing fire. 

22. Explain the operation of common matches. 

23. Of safety matches. 



HOUSE WARMING. 143 



CHAPTER 12. 

HOUSE WARMING. 

Desirable Temperature for Rooms. — Through- 
out the temperate and colder regions of the earth, 
man finds it necessary to employ means for artificially 
warming his home. In this he aims to secure an in- 
door temperature which will give comfort and be con- 
ducive to health. No exact temperature can be 
definitely named as being under all circumstances most 
advantageous. The bodily susceptibilities and require- 
ments of different persons for heat vary considerably ; 
a middle-aged, vigorous man may find no discomfort 
from cold in a room heated only to 59° or 60° F. 
while an enfeebled or sickly person may shiver at 70° 
F. It is evidently advisable, therefore, that a medium 
temperature should be secured, and the individual 
peculiarities be met as nearly as possible by suitable 
amounts of clothing. For the majority of human 
beings, a house temperature of 62° F. to 68° F. will 
be found most agreeable and beneficial. 

Primitive Fire - places. — Many methods of 

warming dwellings are known, of these the open fire- 
place properly claims our first attention, by reason of 
its great antiquity. Among ancient nations the open 
fire was the only known means of house warming, 
and the primitive fire-place was a very crude affair. 
The chimney is a modern invention, being now but 



144 DOMESTIC SCIENCE. 

about 600 years old. Before the thirteenth century, 
dwellings were warmed by a method which is still 
exemplified in the huts of the Esquimaux — the fire 
being on the floor near the middle of the room, and 
the smoke escaping as best it may by the doorway and 
through a hole in the roof. 

Even among the classical Greeks and Romans, but 
little real advancement was made over this primitive 
and dirty practice. However they had vessels specially 
provided as fire-holders ; these were known as braziers, 
and consisted each of a pan mounted on a tripod of 
convenient height, the whole being ornamented with 
carving and symbolical devices.* 

Early Forms of Open Grates. — The invention 
of chimneys was soon followed by that of fire-places 
proper. The first of these consisted of a huge square 
opening in the wall ; but a small part of this space, 
however, was actually used for the fire, the remainder 
being occupied by seats along the sides. Count Rum- 
ford pointed out some of the many defects of such a 
structure; he showed that the jambs or side walls, if 
built so as to directly face each other, that is, at right 
angles to the back of the fire-place, would simply 

* Dr. Youman says of the Roman fire-place: "They (the Greek* 
and Romans) kept fires in open pans called braziers. Those of the 
Romans were elegant bronze tripods, supported by carved images 
with a round dish above for the fire. A small vase below con- 
tained perfumes, odorous gums and aromatic spices, which were 
used to mask the disagreeable odor of the combustive products. 
The portions of the walls most exposed were painted black, to 
prevent the visible effects of smoke, and the rooms occupied in 
winter had plain cornices and no carved work or mouldings, so 
that the soot might be easily cleared away. 



HOUSE WARMING. 145 

reflect the heat rays back and forth between them ; 
whereas if the walls were placed at a widening angle 
with the back, according to the laws governing the 
reflection of rays of force, much of the heat and light 
would be thrown into the room. He concluded that 
the best angle at which the jambs could be set was 
135° with the back of the hearth. 

Essentials of an Efficient Fire-place. — The 

modern fire-place is by comparison a dwarfish struc- 
ture ; the open space leading into the chimney above 
the grate is reduced to a minimum, and the grate itself 
is made to project into the room. In England, the 
open grate remains still in general use, and some im- 
provements are there being introduced. The follow- 
ing features are considered by many English authori- 
ties (notably Parkes and Teale) as essential in good fire- 
places : The back of the grate should be about one -third 
as wide as the front ; the sides set at the angle of 135° ; 
the sides and back should be of fire-brick; the back 
should be inclined forward, that the flames may play 
upon it, the whole fire-place being carried well 
forward into the room ; the chimney throat should 
be narrowed as much as possible ; and the fire-place 
and chimney should be built in the inner walls of the 
house, so that the escaping heat may do some good in 
warming the upper rooms. 

Advantages and Disadvantages of Open 

Grates. — Many people speak in favor of the open 
grate as a heating device, and others present strong 
objections to its use. The brilliant glare of the burn- 
ing fuel, fully exposed to our view, imparts a cheerful 



146 DOMESTIC SCIENCE. 

influence ; it is in the nature of man to love warmth 
and light, and therefore he has pleasant preferences for 
the open grate: — and farther, there are many sub- 
stantial benefits arising from its use. The heat 
derived from a clear, open fire is almost entirely 
radiant heat, the air of the room never becoming burnt 
or excessively heated, and, farther, the fire does much 
to promote eflScient ventilation. On the other hand, 
open fire-places are dusty and dirty additions to a 
room ; ashes and soot are sure to escape from them 
into the apartments ; the radiant heat warms chiefly 
the side of persons and objects that is directed toward 
the fire, and in the coldest weather, when the 
efficiency of our heating appliances is taxed the most, 
this inequality of warmth is found most distressing. 
In addition, open grates do not secure to the room a 
uniform temperature ; but very inadequate regulators 
of the combustion, such as dampers and valves, are 
provided, and the varying intensity of the burning as 
the fuel in the grate becomes low and is then replen- 
ished, will effect rapid changes in the temperature of 
the room. As regards economy of fuel, nothing can 
be said in favor of the open hearth ; experience has 
demonstrated that the best grates of modern con- 
struction allow fully 70 per cent, of the heat to escape 
up the chimney, and in poorly constructed grates the 
proportion of loss may reach even 90 per cent. 

Stoves of various forms are now in common use 
for domestic warming. A stove may be described as 
a box, usually of metal, so constructed as to favor the 
combustion of fuel placed within it, and to allow the 



HOUSE WARMING. 



147 



ready removal of the gaseous products of the burning-. 
Stoves communicate heat to the room, partly by radia- 
tion but mostly by convection. The air in contact 



VotJirUxits 






:BotJirJ>.iii 




Cpetvttfs fir Cold ■^■" 



Fig. 64. 
Double-case stove. 



with the heated surface becomes warm, in consequence 
of which it rises and gives place to a quantity of 



148 DOMESTIC SCIENCE. 

colder air. The air of these rising currents coming in 
contact with the colder ceiling and walls, contracts and 
sinks ; thus circulating currents are created within the 
room. The pipe which leads from the stove to the 
chimney opening imparts much heat to the room ; and 
this effect is materially increased if elbows are placed 
in the pipe. The reason for this is simple — the cooling 
of the heated gaseous contents of the pipe can occur 
only at the surface of the column ; such process will be 
necessarily slow, and much of the heat will be carried 
to the chimney ; whereas if the current be broken up 
as by means of angles in the pipe, a circulation 
within the moving column will be caused, and more 
air will come in contact with the pipe walls, thus 
favoring the transmission of heat into the room. Figure 
64 illustrates the essential parts and action of the 
double-case stove. 

Advantages and Disadvantages of Stoves. — 

stoves are of but slight appreciable benefit in room 
ventilation ; indeed, it is said to their discredit that 
they are of actual detriment, through allowing the 
escape of injurious gases from the fire. In stoves of 
poor construction, and in the best of stoves badly 
managed, this charge is certainly well founded; but 
good stoves under efficient control are not necessarily 
as detrimental to health as has been claimed. How- 
ever, if the iron walls of the stove become too highly 
heated, poisonous gases, principally carbon monoxide, 
will escape from the fire into the room. Hot iron, 
especially if it be cast iron, is readily permeable to 
the deadly carbon monoxide, as also to other gaseous 



HOUSE WARMING. 149 

products from the fire box. Heated iron surfaces are 
apt to char the organic impurities of the air in contact 
therewith, imparting to it a foul smell, and other in- 
jurious properties. These ill effects may be prevented 
in a great measure by using stoves with large radiat- 
ing surfaces, so that no necessity exists of over-heating 
any part. The fire-box of heating stoves should be 
surrounded by fire-brick or other non-conducting 
material : such a casing would assist in regulating the 
temperature changes resulting from the varying inten- 
sity of the fire. Another decided disadvantage attend- 
ing the use of stoves lies in the consequent dryness of 
the atmosphere. As air becomes warmed, its capacity 
for moisture increases, and the relative humidity of 
the air is greatly diminished. This may be partially 
overcome by placing open vessels of water on the 
stove or about the room. Though the use of stoves is 
attended by many serious disadvantages, it is safe to say 
that their demerits have been in some cases over -stated 
to the raising of a strong popular prejudice against 
them. Good stoves if large and well supplied with 
draught-valves and dampers,* may be used in house 
warming with great success. 

Warming' the Lower Portions of Rooms. — All 

the heating arrangements thus far described, tend to 
render the upper parts of the rooms warmer than the 

* The method of placing a damper or regulating valve in the 
pipe is a bad one ; since when such a valve is closed the gaseous 
products of combustion will surely be thrown into the room. 
The draught regulators should be so placed as to control the 
admission of air to the fire, not arranged to check the escape 
of gases. 



150 DOMESTIC SCIENCE. 

floors, which condition is directly opposed to the 
requirements of health ; cold feet are the precursors 
of many forms of illness. The methods yet to be 
referred to promote the distribution of heat at the 
floor. 

Warmed Air is extensively used as a medium in 
domestic heating. In this system, fresh air from 
mthout is carried to the furnaces by means of pipes 
and there it is raised to the proper temperature ; thence 
it is carried through distributing pipes to the rooms to 
be warmed, and then discharged through register 
apertures in walls and floors. The most serious 
defect of the warm-air system lies in the fact that the 
air becomes relatively dry, being in some cases 
actually scorched, and consequently tainted from the 
charring of the contained organic matter. 

Steam Warming" is held in high favor as a means 
for heating dwelling houses and large buildings. The 
essential features of the process are these : steam is 
generated in a properly constructed boiler ; the vapor 
is conveyed through pipes to the apartments that are 
to be warmed : there the steam is passed through one 
or more radiators (^Fig. 65)consisting of a pipe arranged 
in many parallel sections. In condensing, the steam 
imparts its heat to the air of the room. The latent 
heat of vaporization has been already explained ; 
(see page 1 25) — It will be remembered, that in passing 
from the liquid state at the boiling temperature (212° 
F. or 100° C.) to steam at the same temperature, 537 
times as much heat is absorbed as would be required 
to raise the temperature of the same amount of water 



HOUSE WARMING. 



151 




Fig. 65. 
Steam radiator. 



1^ C. This latent heat, though not measurable by 

the thermometer, is re- 
tained by the steam ; and 
in the condensation of 
the latter, the whole 
amount of heat is again 
liberated. Thus water 
may be vaporized in the 
cellar, and the steam 
may be made the carrier 
of heat into the most 
distant parts of the 
house. How admirable 
is the operation of this 
principle ! how cleanly, 
efficient and economical is this method over that of 
grates or stoves in rooms, with their inevitable accom- 
paniments of dust and dirt, irregular temperature, 
uncontrollable draughts, woful waste of energy ! 
The boiler may be situated at any reasonable distance 
from the rooms to be warmed. If far removed, how- 
ever, it is necessary to protect the pipes with coatings 
of non-conducting material, else much heat will be 
lost on the way. The conducting pipes are usually 
wrapped with many layers of asbestos fibre ; then 
with hair felt, and outside of this with several thick- 
nesses of stout paper ; on this, strips of wood are 
laid lengthwise and the whole is bound together by 
wire. The pipe thus wrapped is inclosed in a wooden 
tube, usually a hollowed log. Such insulation is not 



152 DOMESTIC SCIENCE. 

needed in cases wherein the pipes are not exposed for 
any great length. 

Wapm Water Warming". — The warming of 

houses through the medium of warm water depends 
for its efficacy upon the high specific heat of water 
(see page 126), by virtue of which it absorbs tor a 
given rise of temperature a greater amount of heat 
than does any other liquid, and in cooling through a 
given range of temperature a correspondingly large 
amount of heat is given out. 

In the Low Pressiire System of heating by water, 
the pipes are so connected with the boiler as to allow 
a complete circulation ; the water returning to the 
boiler after having traversed the circuit of pipes. 
From the highest point in the course of the pipes a 
vent is provided for the escape of steam and heated 
air. The water in this system can never exceed in 
temperature the boiling point — 212° F., and therefore 
no scorched or excessively dry state of the air i§ 
possible. 

The method known as the High Pressure System 
requires the use of very stout pipes without a vent. 
No boiler being used, the pipes pass directly through 
the furnace and no escape being provided, the inclosed 
water becomes heated under pressure ; its tempera- 
ture may therefore be raised far above the ordinary 
boiling point ; still, as there is no room for ex- 
pansion, steam is not produced. In this system, the 
water is sometimes raised to a temperature above 
300° F. 



HOUSE WARMING. 153 



REVIEW. 



1. What is your opinion as the most desirable general indoor 
temperature? 

2. State what you know of the antiquity of the open fire 
place. 

3. Describe the Roman fire place. 

4. Give reasons for your opinion as to the desirability of 
open fire places in rooms. 

5. State the essential features of a good fire place. 

6. How may stoves vitiate the air of rooms? 

7. Explain the operation of the double-case stove. 

8. State the essential features of a good heating stove. 

9. Where should the damper or regulating valve be placed in 
a stove? 

10. Explain the method of heating rooms by warmed air. 

11. Explain the process of steam warming. 

12. Explain the principle of heating rooms by means of warm 
water. 

13. Explain the low pressure system of water warming. 

14. Explain the high pressure system of water warming. 



154 DOMESTIC SCIENCE, 



CHAPTER 13. 

LIGHT AND LIGHTING. 

Lig'ht, Natural and Artificial. — During the 

daytime we depend for light directly upon the rays 
that come to us from the sun ; this we call natural 
light; throughout the dark hours, we adopt various 
means for the local production of light ; this we call 
artificial light. In reality these terms are misleading ; 
the light of lamp and candle is natural light ; it results 
from the combustion of various animal and vegetable 
matters, all of which grow under the influence of the 
sun's energy. 

Daylight is free to all ; we are only required to 
provide for its admission to our homes. It is not 
doled 'out to us by the pound or the quart; no com- 
pany's agent calls to read the metre and prepare the 
bill of our indebtedness. Light, the purest and the 
best that the physical eyes of man have ever come to 
know, is showered with a Creator's liberality upon the 
world. It floods all places that are open to it. Yet 
how careless we grow as to its distribution and use ! 
Physiologists declare to us that light is as essential as 
is warmth to the welfare of the body. Our homes 
then should be well lighted. 

Lig'ht in Dwelling's. — It is true that the delicate 
organs of sight may be seriously impaired through 
exposure to light of unusual brilliancy ; but the eye 



LIGHT AND LIGHTING. 155 

strain induced by deficient illumination, is a far more 
frequent cause of sight deterioration. The illumina- 
tion within dwelling rooms should be such as to pro- 
duce in the eye a feeling of ease and comfort ; no strain 
should be experienced when closely viewing any object 
within the range of vision. For a i^erson sitting at 
the table reading or writing, the light should come 
from above as through a skylight, or from the left and 
back. In this way the paper or book is well illumi- 
nated, and the shadow is thrown away from the right 
hand. 

Luminosity of Flames. — For artificial illumin- 
ation, the methods most commonly employed depend 
upon the combustion of certain substances, whereby a 
luminous flame is produced. An exception to this is 
seen in the case of the electric light. As has already 
been stated, flame is due to the combustion of gases ; 
solid fuels may evolve great heat and yet their com- 
bustion is flameless. Yet many flames are but slightly 
luminous ; for example, hydrogen burning with a very 
intense heat emits but a very feeble light. The flame 
of the common spirit lamp, depending upon the com- 
bustion of the vapor of alcohol, is almost entirely 
non-luminous. The luminosity of flame is due to the 
incandescence of solid particles which are present with 
the gas. The most intense artificial lights are pro- 
duced by the incandescence of solids. Many of the 
carbon particles in the candle vapor are heated to 
incandescence, the supply of oxygen is insufficient 
to burn them with undue rapidity ; they therefore 
shine. In an ordinary flame, (figure 66,) several dis- 



156 



DOMESTIC SCIENCE. 



tinct parts are discernible ; A, a dark, central core, in 
which region no combustion is possible because of the 
absence of air ; B, a luminous cone ; and C, an outer 
envelope. 

The Blowpipe. — The intensity of combustion in 
an ordinary flame may be greatly increased by means 
of the mouth blowpipe; such as is used by jewelers, 
chemists and others. The manner of using the instru- 
ment is shown in figure 66. By means of such a pipe, 




Fi.2. 66. 
Candle flame and mouth blowpipe. 

air may be blown into the flame ; the flame then be- 
comes a solid one, the combustible materials are more 
rapidly and more completely burned ; few solid parti- 
cles have time to become incandescent before they are 
consumed; the result is a bluish, hot, but non-lumi- 
nous flame. 



LIGHT AND LIGHTING. 



157 



The Kerosene Lamp. — There was a time when 
caudles were the commonest of household illuminants. 
The structure of candles and the general nature of 
their flame have been already noticed. The place of 
candles in domestic lighting has now been taken by 
lamps in which certain inflammable oils are burned. 

A lamp of modern construction (figure 67) consists 
essentially of a cistern, 6, for holding oil ; supported 

on a base or pillar, a ; a 
wick, c, for conveying the 
fluid to the place of burn- 
ing ; a burner, e, for the 
support of the wick and for 
the proper distribution of 
air about it ; this is usually 
provided with a rachet, d, 
by which the wick may be 
raised or lowered ; next a 
chimney of glass, /', to 
shield the fl ame from the dis- 
c's- 67. turbing effects of draughts. 
Simple form of lamp. The wicks that were first 
made were shaped like a solid cylinder ; those of later 
times are flat. Dr. Franklin demonstrated in the case 
of candles, that two small wicks burned side by side 
would give greater light than a single wick of double 
size ; this fact is due to the greater surface exposed by 
the two wicks. The advantage of spreading out the 
wick fibres thereby enlarging the surface will be readily 
seen. 
The Arg-and Lamp. — About i790, A. D., one 




158 



DOMESTIC SCIENCE. 



Argand, of Geneva, invented a lamp in which the wick 
was arranged as a hollow cylinder ; this is still in use, 
and is known as the Argand lamp. The general fea- 
tures of this lamp will be understood from an inspec- 
tion of figure 68, which shows the complete lamp, and 
a section of the same. With such a lamp, a large cylin- 
drical flame is produced. By a peculiar construction 
of the burner, air is introduced into the interior of the 
flame, so that a more perfect combustion, with a con- 





Fig. 68. 
Argand lamp and section of same. 

sequent increase of light, is the result. The wick 

may be raised or lowered so that the size of the flame 

will be proportional to the air current. A valuable 

improvement on the original Argand lamp was made 

by Lange, a Frenchman. He proposed a narrowed 

chimney tube, one having a shoulder in the region of 



LIGHT AND LIGHTING. 159 

the flame. The effect of such a chimney is to deflect 
the outer air current upon the flame, whereby a still 
greater efficiency is secured. With a lamp of this con- 
struction it is possible to burn without difficulty the 
heavier and poorer oils, because the free supply of air 
favors a very complete combustion of the carbon, 
without the production of smoke. The Argand lamp 
is noted for the steadiness of its flame ; it is well 
adapted to the writing table, and is commonly and 
appropriaiely called the Students' Lamp. 

The reservoir of oil is set on the side so as to be 
safely removed from the heated region of the flame. 
The reservoir proper is inverted in an outer vessel, 
and the contained liquid is held in position through 
pneumatic pressure, and is conveyed to the wick only 
as fast as used. 

Shadows thpown by Lamps. — A serious objec- 
tion to the use of the Argand lamp for general 
illumination is based on the shadow thrown by the oil 
reservoir. The cistern of common, flat -wick lamps 
is sometimes so shaped as to throw an objectionable 
shadow. The larger the cistern, the more extensive 
will be its shadow ; yet small oil holders are objec- 
tionable, because the level of their liquid contents falls 
rapidly as the burning proceeds, thus increasing the 
distance between the oil and the burner, with a conse- 
quent diminution of the supply through the wick, and 
a very marked decrease of li^ht. 

Hollow-wick Lamps. — Many forms of hollow 
wick lamps are now in the market. The appearance 
and construction of an efficient kind may be understood 



160 



DOMESTIC SCIENCE. 



from figure 69. The large wick is placed around the 
hollow cylinder, through which air is carried from 
below. The base at its place of support is either scal- 
loped or perforated, so as to allow the ready passage 
of air into the central channel, a. A funnel-shaped 
distributor deflects the inner column of air against the 
flame. Lamps of this construction afford much light ; 
but they are not well adapted for the writing desk or 




Fig. 69. 
Hollow wick lamps. 

reading table, because of the great heat resulting from 
the large consumption of oil. 

Lamp Shades. — it is advisable to surround the 
lamp chimney with a convenient shade, so as to mod- 
erate the intensity of the rays that reach the eye. It 
is not desirable that light pass in an unbroken line 
from its source to the eye ; its efficiency depends upon 
the illumination of the objects to be viewed ; and ex- 



LIGHT AND LIGHTING. l6l 

periment has demonstrated that if the eye in viewing 
an object receives from other sources any rays of light 
of greater intensity than those reflected from the ob- 
ject itself, the usual impression is weakened, and the or- 
gans of sight are unnaturally strained. The value of a 
shade in deflecting the light downward upon the table 
will be readily seen. The best ^shades are made of 
ground glass or porcelain, and are colored on the 
inside sky-blue. Artificial light from candles or oil 
lamps is deficient in certain of the component colors 
of white light, and the blue shades will partly supply 
the missing tints. Shades so colored afford less intense 
but purer illumination. 



REVIEW. 

1. Why should dwelling houses be well lighted? 

2. From which direction should the light come for a person 
sitting at a desk? 

3. Which are the commonest devices for artificial illumina- 
tion? 

4. Describe the parts of an ordinary flame. 

5. Describe the mouth blow pipe. 

6. Explain the use of the blow pipe in increasing the heat of 
flames. 

7. Describe the parts of an ordinary kerosene lamp. 

8 . Show the effect of a large wick as compared with a small 
one. 

9. Describe the Argand lamp. 

10. Show the value of the peculiar chimney of the Argand 
lamp. 

11. Describe other forms of hollow-wick lamps. 

12. What is the use of a lamp shade? 

13. State the essential features of a good lamp shade. 



162 DOMESTIC SCIENCE. 



CHAPTER 14. 

LIGHTING CONTINUED : COMMON ILLUMINANTS. 

# 

Illuminating' Fluids. — Reference has already 
been made to candles as sources of light, let us now 
consider other illuminants. Among the common 
illuminating fluids, are fish oil, lard oil, colza oil, tur- 
pentine, and kerosene. The last named is the common 
household illuminator. Kerosene is a product of the 
distillation of petroleum, and, as offered in the 
market, is of specific gravity* lower than that of 
water, clear and transparent, the best grades showing 
a blue tint by reflected light. 

Flashing* Point and Fire Test. — In burning, 
the oil is first converted into vapor ; this takes fire at 



* The Specific Gravity of a substance is the ratio between its 
weight, and the weight of an equal bulk of some other substance 
taken as a standard. The common standard for solids and liquids 
Is pure water. AYhen we say that the specific gravity of iron is 
7.5, we mean that a piece of iron weighs 7.5 times as much as an 
equal bulk of water; so we say alcohol has a specific gravity of .8; 
that is, any volume of alcohol weighs .8 as nwich as the same 
volume of pure water. The following list of specific gravities of 
a few common substances may be of use to the student: 



Pure water 


1.00 


Cork - 


•24 


Alcohol 


.8 


Pine wood 


.66 


Turpentine 


.87 


Ice 


.92 


Olive oil 


92 


Marble 


2.8 


Milk 


1.03 


Iron 


7.5 


Mercury 


- 13.6 


Lead 


- 11.4 


Gold 


- 19.4 


Platinum 


- 22.06 



COMMON ILLUMINANTS. 163 

a temperature which varies for different kinds 
of oil ; this degree of temperature is known as the 
flashing 'point ; at a somewhat higher temperature the 
liquid burns continuously, this is known as the fire 
test point. Evidently the use of oil of a low flashing 
point is attended by great danger from the liability of 
the mixture of air and vapor within the oil holder to 
explode. In many parts of the United States and in 
Europe, there are legal enactments specifying the low- 
est flashing point that is permitted in oils offered for 
public sale. The writer has found in the market 
varying grades of kerosene, of flashing points ranging 
from 75° F. to 135° F. ; and of fire test as low as 110° 
F. : and as high as 300° F. 

Danger from Kerosene Lamps. — The strin- 
gency of the laws has done much to restrict the sale of 
light oils ; and it is pleasing to contemplate that acci- 
dental explosions in lamps are now infrequent. With 
the best of oil, however, careless management of the 
lamp may lead to disastrous results. The common 
practice of extinguishing the flame by blowing down 
the chimney often causes ignition in the oil chamber, 
in which case an explosion is almost inevitable. Allow- 
ing a lamp to burn itself out is a dangerous practice ; 
the wick smoulders, and a spark or a glowing ember 
may reach the oil chamber, and cause a destructive 
explosion. Some improved forms of lamps are pro- 
vided with extinguishers; and others have an auto- 
matic attachment by which the flame is put out if the 
lamp be overturned. With the best of contrivances, 
and under the most favorable conditions, great care 



164 DOMESTIC SCIENCE. 

in the management of the lamp is essential to safety. 

Coal Gas is used in large towns as an illuminant. 
It consists of the volatile matter of coal. The pro- 
duction of gas is carried on at the central works, the 
gas being then distributed through underground mains 
to the consumers. Good gas is a cleanly, convenient, 
and an efficient material for illumination ; though its 
presence in the house entails certain dangers demand- 
ing constant vigilance on the part of the inmates. An 
accidental escape of gas into the rooms may form with 
the air an explosive mixture ; and the smallest amount 
of coal gas in the air of the house, must be regarded 
as a poisonous addition. The inhalation of any con- 
siderable amount of coal gas produces asphyxia and 
speedy death. It is well for us that the substance 
possesses a disagreeable odor ; for by it we may often 
recognize the presence of the poison, and we should 
seek to preserve our sensitiveness to its effects. The 
gas is consumed at convenient points along the line of 
the supply pipes, burners of different forms being 
employed ; the commonest burners are the fish-tail, 
the bat's wing, and the Argand. Gas burners may 
be provided with an electric attachment, so that the 
passage of a current from a local battery opens the 
valve, thus allowing the gas to pass, and ignites it as 
it issues. With such a contrivance, it is only neces- 
sary to press the circuit button, which maybe located 
in any convenient place, and the gas is turned on and 
lighted. A second push stops the flow of gas, and, of 
course, extinguishes the light. 

Water g'as is the name of another illuminant, which 



COMMON ILLUMINANTS. 165 

is produced by the decomposition of steam through 
contact with incandescent carbon. The oxygen from 
the steam unites with the carbon to form carbon mon- 
oxide, while the hydrogen of the steam is freed. 
Such a mixture of hydrogen and carbon monoxide 
burns with considerable heat, but with little light ; it 
is necessary therefore to enrich the gas, and this is 
accomplished by mixing it with the vapors of naphtha, 
gasoline, or other highly volatile mineral oils. 

VapOP Gas. — Another method of using the vapors 
of light oils as illuminants consists in passing a current 
of air through such liquids, whereby the air becomes 
saturated with combustible vapors ; in this state it is 
conveyed through pipes to the place desired and there 
burned in ordinary gas burners. The apparatus used 
in the production of this vapor gas is simple and port- 
able ; it may be operated in any dwelling house. Care 
is requisite in using the gas, for dangerous explosions 
have occurred from the premature lighting of the 
vapor laden air. 

Ventilator Burner. — All the methods of house 

lighting thus far considered possess the serious defect of 
contributing largely to the pollution of the atmos- 
phere.* Various forms of ventilator burners have 
been made ; these are designed to carry away through 



*Dt. Toumans says : — " A candle (six to the pound) will consume 
one -third of the oxygen from 10 cubic fett of air per hour, while 
oil lamps with large burne's willc lange in the Same m av 70 feet 
per hour. A« t* e dt grees of change in ihe air correspond witli 
the amo' nt of light evolved, it is plain that gas illumination 
alters the air most rapidly. A cubic foot cf coal ga*! consumes 
from 2 to 2 and a half cubic feet of oxygen, and produces J to 2 



166 DOMESTIC SCIENCE. 

flues the objectionable products of combustion ; but 
all of such contrivances are expensive and inconvenient, 
and none of them have come into very general use. 
Vitiation of the atmosphere is inevitable while 
methods of illumination are direct[y dependent upon 
processes of combustion. 

Electric Lig'htS. — Such objections are inapplicable 
in the case of electric lighting. Electric lamps are of 
two kinds, the arc lamp and the incandescent lamp. 
In the arc lamp (figure 70) the light results from the 
passage of a strong current through rods of gas carbon 
set end to end, which are separated at the place of 
contact. Some carbon particles become volatilized 
through the great heat caused by the current, these 
form an incandescent bridge between the separated 
rods. The arc light is in favor for illuminating streets 
and large buildings. For illumination on a smaller 
scale, however, the incandescent lamp (figure 71) is 
preferable. This consists of a globe of glass, sealed, 
and containing some inert gas such as nitrogen or car- 
bon dioxide, which will not support combustion. A 
fine, hair-like filament of carbon, B, is placed within 
the globe, the ends connecting with binding screws, to 
which the line wires of the electric circuit can be 
joined. As the illuminating effect is not due to the 
chemical energy of combustion, it is plain that this 
method of lighting does not result in vitiation of the 

cubic feet of carbonic acid. Thus every cubic foot of gas burned 
imparts to the atmosphere 1 cubic foot of carbonic acid, and 
charges 100 cubic feet with 1 per cent, of it making it unfit to 
breathe. A burner which consumes 4 cubic feet of gasper hour 
spoils the breathing qualities of 400 cubic feet of air in that time." 



COMMON ILULMINANTS. 



167 



air. Incandescent lamps may be operated under 
water, and in this war aquaria may be beautifully and 
brilliantly illuminated. 

Waste of Enepg-y in Illumination. — Even the 

best of our methods of artificial illumination are wofully 





Fig. 70. 
Electric arc lamp. 



Fig. 71. 
Incandescent electric lamp. 



wasteful of energy. This is largely due to the fact 
that much of the energy developed by combustion or 
through electrical resistance, manifests itself as heat 
instead of as light. Lamps are intended primarily as 



i68 DOMESTIC SClfcNCE. 

sources of light, and not as heating devices, yet the 
results of recent experiments by Professor Langley 
show that 99 per cent, of the energy of candle and 
lamp flames is lost as far as illuminating effect is con- 
cerned ; and that in electric lighting, fully 50 per cent, 
of the total energy fails to appear as light. 

The FiPe-fly'S Lig'ht. — Experiments are now in 
progress to test various methods of producing light 
with a minimum of loss through heat. Upon this 
subject considerable interest has of late been stirred 
by the phenomena attending the fire -fly's glow, and 
other examples of natural phosphorescence. At pres- 
ent, man is unable to produce light equal in intensity 
to that of the fire -fly, without an accompanying tem- 
perature of nearly 2000° F. ; yet the light- giving 
power of the insect named is exercised without devel- 
opment of sensible heat. 

Referring to his experiments on the fire-fly's light. 
Professor Langley says: "We repeat, that Nature 
produces this cheapest light at about one four -hun- 
dredth part of the cost of the energy which is ex- 
pended in the candle-flame, and but at an insignificant 
fraction of the cost of the electric light, which is the 
most economic light which has yet been devised : and 
that finally there seems to be no reason why we are 
forbidden to hope that we may yet discover a method 
(since such a one certainly exists, and is in use on the 
small scale), of obtaining an enormously greater re- 
sult than we now do from our present ordinary means 
for producing light." 



COMMON ILLUMINANTS. 169 



REVIEW. 



1. Which are the principal oils used for illumination ? 

2. What is kerosene ? 

3. Define "flashing point:" "fire test point." 

4. Show the value of high flashing and fire test points in 
illuminating oil. 

5. Discuss coal gas as an illuminant. 

6. Water-gas. 

7. Vapor gas. 

8. What great advantage has electric illumination over the 
methods which depend upon combustion ? 

9. Which are the two principal kinds of electric lamps ? 

10. Describe the arc lamp. 

11. The incandescent lamp. 

12. Show the great waste of energy in the ordinary methods 
of household illumination. 

13. Name some instances of natural phosphorescence. 

14. State what you know of Langley's experiments on the 
fire-fly's light. 



PART II. 



WATER. 



WATER ITS OCCURRENCE. 173 



CHAPTER 15. 

WATER ITS OCCURRENCE. 

Water Widely Distributed. — Water is indispen- 
sable in many of the processes of life ; and in domes- 
tic operations it is a prime necessity. Without it, the 
intricate machinery of civilization would be inactive ; 
and all physical forms of life — the bodies that serve 
as tenements for deathless spirits — would cease to 
exist. Indeed, the structure of even the dead things 
of earth depends largely upon the presence of water. 
In each of the three great divisions of created things, 
minerals, plants, and animals, water is present as an 
essential constituent. 

Water in Minerals. — in minerals it forms a very 
considerable proportion of the total composition, and 
in many cases gives to the mineral bodies their char- 
acteristic color and form. To illustrate this, take a 
crystal of copper sulphate, — blue vitriol, or blue stone, 
as it is commonly called : carefully heat it in an iron 
spoon, or better, in a clean, dry test tube. Very soon 
steam is seen rising from the crystal ; in the tube this 
vapor condenses on the colder part of the glass, and 
may there accumulate till it gathers in drops and 
trickles down the tube in a stream. Now that the 
water has been expelled, instead of the beautiful, 
transparent " blue stone," we have left only a grayish 
powder, entirely undeserving of the popular name, A 



174 DOMESTIC SCIENCE. 

drop of water added to this powder will partially 
revive the azure tint, but the transparency and the 
symmetrical form have gone forever. The experiment 
teaches us that the presence of water is essential to 
the crystalline arrangement of particles within the 
mass. A transparent piece of alum treated in the 
same way will evolve large quantities of liquid, and 
will assume the appearance of a white, opaque pow- 
der — the " burnt alum " of the druggists. Chemical 
analysis has proved that water is ordinarily present in 
the minerals named below, as specified : 

Per cent, water. 

Calcium sulphate (gypsum) - - 20.9 

Copper nitrate .... 30.1 

Copper sulphate (blue vitriol) - 36.1 

Zinc sulphate (white vitriol) - 43.9 

Iron sulphate (green vitriol) - - 45.3 

Borax ..... 47.1 

Soda alum ..... 47.3 

Magnesium sulphate (Epsom salts) - 51.2 

Sodium sulphate (Glauber salts) - 55.9 

Sodium carbonate (washing soda) - 62.9 

Water of Crystallization. — The common desig- 
nation of water so combined in minerals is " water of 
crystallization.'' By mere exposure to dry air, many 
of the salts named in the table allow some part of the 
contained water to escape ; such process is called 
efflorescence. To observe this, take a few clear crystals 
of Glauber salts, or of washing soda; put them in an 
open dish, and set in a warm, dry atmosphere; the 
substance soon loses its transparency and becomes 
opaque and friable. This property of solids contain- 
ing water of crystallization is well known to the 



WATER ITS OCCURRENCE. 175 

dealers in such substances ; grocers and druggists 
usually store efflorescent salts in tight cases, so as to 
prevent the escape of the water of crystallization, and 
a consequent decrease in weight. Washing soda, if 
exposed in open vessels, may lose over half its 
weight. 

Water Absorbed by Minerals.— Beside the water 

commonly combined in mineral bodies, and forming 
an essential constituent of the same, large quantities 
of the liquid are sometimes absorbed and mechanically 
retained by minerals. Coal frequently contains even 
ten per cent, of water. Ores taken from the mines, 
though seemingly dry, are often so heavily laden with 
water as to necessitate a drying process preliminary to 
the furnace treatment. 

Water in the Vegetable Kingdom. — In the 

kingdom of plants water is no less widely distributed 
nor less essential as an item of their composition. Its 
presence in vegetable bodies may be easily demon- 
strated. Place within a dry test tube a chip of wood, 
a little sawdust, starch, or any other plant product — 
better select an apparently dry substance, that the 
illustration may be the more impressive ; — now apply 
heat, taking care not to char or blacken the substance ; 
soon water is evolved as steam, this condenses upon 
the cold portion of the tube. 

Water in Fresh Plant Products.— The follow- 
ing table exhibits the proportion of water in certain 
fresh vegetable substances, the figures being the aver- 
age results of numerous analyses by the author and 
others : 



176 DOMESTIC SCIENCE. 





Per cent. Water. 


Pine wood (Utah) 


- 


40 


Utah apple wood 


- 


42 


Timothy 




70 


Meadow grass 


■ 


72 


Lucern 


. 


75 


Potatoes 


- 


75 


Red clover 


. 


79 


White elover 


. 


81 


Grapes 


- 


81 


Beets 


- 


82 


Apricots 


- 


83 


Apples 


■ 


84 


Carrots 


• 


85 


Gooseberries 


• 


86 


Strawberries 


■ 


87 


Cabbage 


- 


89 


Turnips 


- 


91 


Cucumbers 


- 


97 


Water-melons 


- 


98 



Water in Air-Dried Plant Products.— Through 

exposure to the air, part of this constituent water will 
be lost, but even in air- dried vegetable products, very 
large proportions of water remain, as will be seen 
from this table ; the figures represent average amounts 
as found by examinations of numerous samples : 





Per f'ent water 


Meadow grass hay 


15 


Red clover hay 


16 


Dried pine wood 


15 


Dried wheat straw 


16 


Wheat kernel 


15 


Indian corn 


13 


Rye kernel 


15 


Barley 


14 


Oats 


13 


Buckwheat 


13 


Peas 


14 


Rice 


13 


Oatmeal 


10 


Cornmeal 


13 



i 



WATER ITS OCCURRENCE. 



177 



Absorption of Water by Plants. — Water is the 

medium by which the nutritive matters of the soil are 
carried into the body of the plant. The roots of com- 
mon plants ramify through the soil in great abund- 
ance ; the main root giving off many branches, which 
in turn divide, and subdivide till they become finer 
than hairs. The root hairs are in close contact with 




//v> 



y'ffl^' 



'1-"^, 




vj:o<- 



Fig. 72. 
Rootlet with roothairs; rootlet 
with adhering soil. 



Fig. 73. 

Pressure guage attached to 

a growing plant. 



the soil ; so close indeed that in many cases it is pos- 
sible to separate the adherent soil from a root that has 
been taken from the ground, only by vigorous shaking 
and thorough washing. 

Figure 72 (right sketch) shows the appearance of a 
wheat rootlet with adhering soil just as it was taken 
from the earth ; and the left sketch exhibits the same 



178 DOMESTIC SCIENCE. 

after thorough washing to remove the soil. The nu- 
merous root-hairs are distinctly shown. Through the 
roots large quantities of water are absorbed. 

FOPCe of Ascending" Sap. — The liquid rises 
through the vessels of the stem in the form of sap, and 
in doing so exerts a surprising force. There is a 
method of forcibly demonstrating this (see figure 73). 
If a pressure guage consisting of a bent tube B, with 
mercury in the bulb C, be attached to the stem of a 
growing plant A cut off near the ground, the rising 
sap will lift the column of mercury. In an operation 
of this kind, Dr. Hales found that the pressure 
exerted during the spring of the year by a young 
grape vine supported a column of mercury 32^ inches 
high. This corresponds to a column of water 36^ 
feet in height or to a pressure of 16 J pounds to the 
square inch. Hofmeister found that a common sting- 
ing nettle similarly tested, supported a column of 
mercury 14 inches high, due to a pressure of 7 pounds 
per square inch. The water so absorbed is distributed 
throughout the entire structure of the plant ; many of 
the solid matters which enter the plant in solution are 
retained within the vegetable cells ; while the water 
itself escapes through the countless stomata of the 
leaves. 

Water in Animal Bodies. — in the bodies of 

animals water abounds. A very large proportion of 
the meats, eggs, and milk we buy is water ; this will 
be seen from the following table : 



WATER r 


rs occuF 


LRENCE. 

Per cent, water, 


resh mutton contains 


71 


beef 


- 


73 


" veal 


- 


75 


" pork 


- 


76 


fish 


- 


80 


fowl 


- 


73 


egg 


- 


74 


milk 


- 


87 



179 



The bodies of many of the lower animals consist 
mainly of water. Agassiz, a scientist of high repute, 
examined the body of an aurelia (one of the jelly- 
fishes), from the Atlantic coast of this country ; when 
alive the creature weighed 30 lbs., but when thor- 
oughly dried its body yielded but half an ounce of 
solid matter, — showing over 99.8 water. 

Water in Human Tissues. — ithas been proved that 

the average human body contains water to the extent 
of from two-thirds to three -fourths of its weight. The 
proportion of water present in different organs and 
products of the body will be seen from the following 
exhibit : 









Per cent, water. 


Human teeth 


- 


10 




bones 


- 


13 




muscles 


- 


75 




brain 


- 


79 




blood 


- 


79 to 80 




bile 


- 


88 




milk 


- 


88 to 89 




gastric juice 


- 


97 to 98 




perspiration 


- 


98 to 99 




saliva 


_ 


99 to 99.5 



To supply the body with the requisite amount of 
water, a man of average size has to imbibe about three 
and a half pounds of the liquid daily ; this would 



180 DOMESTIC SCIENCE. 

amount in a year to over 127 gallons. It is, of course, 
not necessary that this quantity of water be actually 
drunk, as a very large part of it is supplied from the 
food. 



REVIEW. 

1. Show the indlspensability of water in many of the pro- 
cesses of life. 

2. Prove that water is an essential constituent of many min- 
erals. 

3. What is meant by water of crystallization ? 

4. Give examples of minerals containing large proportions of 
water. 

5. Explain efflorescence. 

6. What do you know of the occurrence of water in plants . 

7. Give percentages of water in fresh and air-dried plants. 

8. How is water absorbed by plants ? 

9. Describe a demonstration of the pressure exerted by rising 
sap in plants. 

10. State the results of experiments of this kind on certain 
plants. 

11. Give illustrations of the occurrence of water in animal 
bodies. 

12. What do you know of the occurrence of water in the 
human body ? 



WATER bOME OF ITS UtiES, 181 



CHAPTER 16. 

WATER SOME OF ITS USES AND PROPERTIES. 

Extensive Uses of Water. — Aside from forming 
so extensive and important a constituent of minerals, 
plants, and animals, the uses of water are many and 
varied. In each of its three physical states, as a 
liquid (water itself), as a solid (ice), and as vapor 
(steam), it proves of inestimable service to man. 

Water, in the form of running streams furnishes 
us a continual source of power. Each tiny drop 
pushes against the wheel, an^ the current grinds our 
corn and weaves our cloth ; drives our saws and 
planes, and forces open the vaults in which Nature has 
stored her wealth of sugar and nectar, of oil and of 
wine. In its ocean depths, it forms an efficient and 
easily used road of travel between distant lands ; and 
in both stream and sea it constitutes a home for 
countless forms of animal life, of value to us for food 
and ornament. 

As Ice, it is to us a cheap and an effective protection 
against decomposition ; it stands guard over things 
most perishable, and successfully repulses the ever 
eager spirits of decay and destruction. In this form, 
too, it is held in reserve upon the mountain tops till 
its presence is most needed on the fields and farms be- 
low ; and then, bursting away its frozen bands, it 



182 DOMESTIC SCIENCE. 

hastens down with a merry babble and a joyous laugh, 
like the voice of a happy child awakening from peaceful 
dreams to pleasant play. It carries joy and comfort 
in its course ; the thirsty plants lift up their heads at 
its approach and smile with thankfulness ; the laden 
beast is refreshed, and the heart of man is gladdened. 

As Steam, it drives the wheel of civilization, and 
has done much to put the stamp of progress upon the 
present age, and to establish the superiority of God- 
given mind, over all else upon earth. Its effects have 
surpassed the achievements of the fabled giants of old, 
who were said to run a mile at a stride, and to carry 
houses upon their backs.* ^ 

Neutral PropePtieS of Water. — in physical pro- 
perties, water is the perfection of adaptability to the 
needs of man. In the most of its characteristics, it is 
the -type of neutrality, being odorless, without color, 



* Water is the common carrier of creation. It dissolves the ele- 
ments of the soil, and, climbing as sap up through the delicate 
capillary tubes of the plant, furnishes the leaf with the material 
of its growth. It flows through the body as blood, floatiiig to 
every part of the system the life-sustaining oxygen, and the food 
necessary for repairs, and for building up the various parts of the 
' house we live in.' It comes in the clouds as rain, bringing to ua 
the heat of the tropics, and tempering our northern climate, while 
in spring it floats the ice of our rivers and lakes away to warmer 
seas to be melted. It washes down the mountain side, levelling 
its lofty summit, and bearing mineral matter to fertilize the valley 
beneath. It propels waterwheels, works forges and mills, and 
thus becomes the grand motive power of the arts and manufac- 
tures. It flows to the sea, bearing on its bosom ships conducting 
the commerce of the world. It passes through the arid sands, 
and the desert forthwith buds and blossom as the rose. It limits 
the bounds of fertility, decides the founding of cities, and directs 
the flow of trade aiid wealth. 

Dr. Steele. 



WATER SOME OF ITS USES. 183 

and devoid ^f taste. High flavors and sweets are not 
always pleasant to the palate, and the most subtle per- 
fumes are at times sickening and even injurious in 
their effects. If water possessed positive properties of 
taste and smell, all our foods, into the composition of 
which water so largely enters, and in the cookery of 
which it plays so important a part, would partake 
of the universal flavor, their qualities would be in all 
cases modified, and in many instances destroyed 
thereby. 

Water and Heat. — The properties of water under 
the influence of heat have been dwelt upon in a pre- 
ceding chapter. Its high specific heat, whereby its 
temperature changes are modified and retarded, the 
great amount of heat rendered latent in the fusion of 
ice and in the formation of steam, with some of the 
resulting good effects, have also received attention. 

Freezing" of Water. — in passing from a liquid to 
a solid form, that is in freezing, water observes a 
strange and an anomalous behavior. Solidification, or 
freezing, is the result of cooling, and is usually at- 
tended by contraction in bulk. The principle that 
"heat causes expansion and cold causes contraction," 
applies to water at certain temperatures only. Above 
4° C. or 39.2° F., water expands by heating: below 
that temperature it expands by cooling ; so that a 
piece of ice is larger than the mass of water from which 
it was produced. The ice is therefore specifically 
lighter than the water ; and as a consequence ice floats 
in water. If the contraction of water by cold con- 
inued to the point of congelation, there would be a 



184 DOMESTIC SCIENCE. 

constant rise of warm, and a fall of cold water in the 
body of the liquid undergoing the freezing process, 
till the whole would become solid, and in the case of 
a lake, sea, or ocean, all living things therein would 
be killed. Farther, — if ice sank as fast as formed in 
lakes and seas, it would be beyond the reach of the 
sun's rays, and many tropical summers would be re- 
quired to thaw the ice of one temperate winter. As 
it is, however, ice being a poor conductor of heat, the 
surface layer actually protects the warmer water below 
from undue cooling. 

By reason of the expansion of freezing water, frost 
is a most valued servant to the farmer, breaking up 
the hardened clods, and exposing large surfaces of 
soil to the vivifying action of the air. In an analog- 
ous way the rock-masses of the hills arc burst asunder, 
and thus they are prepared for rapid disintegration 
and speedy conversion into fresh and fertile soils. 

Ice Crystals. — Freezing is essentially a crystalliz- 
ing process, and the microscope will reveal in the 
snowflake and the ice block a symmetry of parts 
analogous to that of the stony crystals of earth. The 
unaided eye perceives the beauties of the hoar frost on 
pavement and window pane ; the glistening spangles 
suggest flowers, fruit, and leaves ; surely the winter is 
not without its flora. To examine the snow flowers 
microscopically, choose a cold day when comparatively 
dry flakes are falling ; catch them upon cold pieces of 
colored glass ; do not touch them or breathe upon 
them ; then examine with a low magnifying power. 
Figure 74 shows a very few of the almost infinite 



WATER SOME OF ITS USES. 



185 



forms of the crystals of frozen water. Each of them 
is composed of six main parts or groups of parts, all 
arranged upon a plan of seemingly perfect symmetry.* 
The prevailing angle at which the spangles are set 
with regard to each other is the same in all. Why 
this constancy? Surely the Great Creator delights in 
order. Should not we, His children, learn to ap- 
preciate the beauties of His wondrous workmanship? 




Fiff. 74. 



Crystals of ice. 

Beautifying" Effect of Water.— it would be 

difficult to find a substance that does more than water 
does in beautifying and diversifying the surface of 



* Professor Tyndall describes a certain fall of snow crystals 
witnessed by him as "a shower of frozen flower-; all of them 
were six-leaved; some of the leaves threw out lateral ribs like 
ferns; some were rounded; others arrowy and serrated; but there 
was no deviation from the six-leaved type," 



186 DOMESTIC SCIENCE. 

our earth and its surroundings. The heavenly tints 
of morn and eve, the varying effects of cloud and mist, 
the glorious bow, which seals the covenant of the 
Creator with His children, and which must ever re- 
main an object of our deepest wonder and admiration ; 
— all are largely due to the water drops suspended in 
the air. The pretty spangles of the hoar frost, the 
ferns and leaves of the winter window, the stars and 
flowers of the snow-flake and the ice block, show the 
operations of the building forces of Nature according 
to the laws of strict and perfect science. 



REVIEW. 

1. State the three physical states of water. 

2. Show some of the uses of water in the liquid state. 

3. Show the uses served by water in the solid state, — as ice. 

4. State some of the uses of steam. 

5. What you know of the physical properties of water? 

6. Describe the exceptional behavior of water in freezing. 

7. Show the great benefits resulting to the world from the 
difference between the specific gravity of water and that of ice. 

8. Describe the action of frost in disintegrating rock and soil. 

9. Describe the freezing process. 

10- What do you know of the crystals of ice and snow? 
11. Show some of the effects of water in beautifying the earth 
and air. 



fcOURCES OF WATER. 187 



CHAPTER 17. 

SOURCES OF WATER. 

Primary Sources of Water. — In view of the 

many and diverse uses of water in the operations of 
life, it is gratifying to note that Nature has supplied it 
in unstinted quantity, liberally distributed throughout 
the world. The water we use is primarily derived 
from the clouds, through the medium of rain and 
snow. A part of the water that falls upon the surface 
of the earth speedily returns to the vaporous condi- 
tion, and is again if ted into the atmosphere. The 
inclination of the ground surface and the nature of the 
soil with respect to its permeability to liquids, will 
determine what proportion of the remainder will run 
off in the forms of streams, and what part will sink 
and percolate through the soil. That portion of the 
surface water that flows away in streams goes to swell 
the rivers of the neighborhood ; and a part of that 
which sinks into the soil, serves to supply the roots of 
growing plants ; the rest of the percolating water will 
probably re -appear at some distant place in the form of 
springs. In the case of porous soil, this percolation is 
rapid, so that in some regions it is found necessary to 
collect the rain water in cisterns as it falls, and store 
it for general use. 

Rain Water is particularly serviceable for many 
household operations on account of its softness, which 



188 



DOMESTIC SCIENCE. 



is a result of its freedom from mineral impurities. 
To procure pure rain-water, the collection should be 
made in an open space ; the water that comes to us 
from the house pipes is usually almost black from the 
impurities that it has washed from the roof. 

Spring's and Artesian Wells. — Much of the 
water that serves our domestic purposes is derived 




Fig. 75. 
Hillside spring. 

from springs. These are numerous in hilly regions, 
providing the rainfall is adequate and the soil of 
proper kind. As the water falls from the clouds 
upon the hills, a part of it sinks into the soil and des- 
cends till it reaches a stratum that is impermeable to 
the passage of water. Here its downward course is 
checked, and the water flows along the impermeable 
layer as along a floor. If this should lead it to the 
surface of a hill, there the water will issue as a Hill- 



SOURCES OF WATER. 



189 



side Spring (see figure 75). If, however, the course 
of the floor -stratum should be such as to carry the 
water below the land surface in the valley, (as il- 
lustrated in figure 76) the liquid may continue beneath 
the earth till it finds or forms a fissure in the earth ; 
from this it escapes as a Fissure Spring, or Main 
Spring (b). By boring or driving into the soil, such 




Fig. 76 
Fissure spring B, and artesian well C. 

subterranean streams may be tapped, the water then 
rises through the pipe, which may be regarded as 
an artificial fissure ; this constitutes the Artesian 

Well (c).* 



♦Artesian wells derive their name from the fact that wells of 
the sort were first made in the province of Artois, France. In 
some parts of the United States, the name "flowing wells" is 
often applied to them. In many sections of Utah, wells of this sort 
are very common; some of them yield per minute from 50 to 100 
gallons of water. 



190 



BOMESTIC SCIENCE. 



Liquids Seek Theip Levels. — The force that 

causes a rise of water through the fissure or pipe will 
be understood from the following simple observations. 
If a tube of glass open at both ends be inserted in a 
vessel of water, the liquid rises within the tube to the 

level at which it stands in 
the outer vessel. f Figure 
77 represents a central ves- 
sel communicating with a 
number of tubes of differ- 
ent sizes and shapes. If 
water be poured into such 
a vessel it will reach the 
same level in each of the 
tubes. This fact warrants 
the oft -used expression, 
''Liquids will find their level.'- It is impossible to 
carry a liquid by its own pressure above the level of its 
source. 

By way of further illustration, prepare the appar- 
atus sketched in figure 78. Provide a good-sized 
funnel, and attach to it a rubber tube. At the other 




Fig. 77. 
Equilibrium of liquids. 



flf the tube be of smtill caliber the water will rise to a level 
higher than that of the liquid in the vessel; this is due to the 
adhesion between the glass and the water. Such adhesive force 
when operating in very small tubes is known as capillary attraction 
the term " capillary" being derived from the Latin capillus, mean- 
ing a hair, ani so applied because the phenomenon manifests 
itself most strongly in small or hair-like tubes. It is by capillary 
attraction that a piece of bread absorbs milk when dipped in the 
liquid; tlia a sponge absorbs water; that a towel dries our flesh. 
We know how efficient is an un-glazed towel over one in which 
the pores are closed by an impermeable gloss. 



SOURCES OF WATER. 



191 



end of the rubber insert a glass pipe. Hold the at- 
tached tube so that the free end is level with the 
funnel-top, and pour water into the funnel ; the li- 
quid rises to the same height in the tube. JSTow lower 
the tube, so that the opening is below the water level 

in the funnel : the water 
now issues as from a 
fountain, and leaps nearly 
to the level of its source 
in the funnel. The fric- 
tion of the flowing liquid 
against the tube, the re- 
sistance of the air through 
which it rises, and the 
force of the descending 
drops as they strike the ris- 
ing stream, prevent the 
J,, ^g exact level being fully 

Liquid rising to the level of its reached. So in the case of 
source. ^j^g fissure spring or the 

artesian well, the tendency of the escaping stream is 
to throw itself to the level of its source in the sur- 
rounding hills. The right-hand tube in figure 77 illus- 
trates the same phenomenon. 

Intermittent Spring's. — There are some springs 
that discharge water at certain seasons only ; these are 
known as intermittent springs. It is believed that 
they are due to some such a formation as is shown in 
figure 79. During a wet season, water would perco- 
late through the soil and gather in the cavern, A ; as 




192 



DOMESTIC SCIENCE. 



soon as it rose above the highest point in the exit pas- 
sage, B, the water would flow to the opening and 
there appear as a spring. The flow would continue 
till the water sank below the entrance to the tube, B ; 
and then would cease till the cavern had again filled to 




■ Fig. 79. 
Possible cause of intermittent springs. 

the former level. This operation is explained by the 
principle of the siphon, page 35. The action may 
be well illustrated with the simple apparatus here 
shown (figure SO). A glass vessel is provided with a 
bent delivery tube. If water be poured into the recep- 
tacle A, till the level of the liquid is above the highest 
point of the tube B, the water will run through the tube 



SOURCES OF WATER. 



193 



and the flow will continue till the liquid in the large 
vessel has sunk below the entrance to the pipe. 

Intermittent springs may be due to other conditions 
than the occurrence of such a cave. In a case similar 

to that shown in figure 
81, during high water 
season, the level of the 
subterranean water may 
reach A, then aflow would 
occur at S : as the under- 
ground water level sinks, 
Pig. 80. however, say to B, the 

Apparatus to illustrate a possible spring WOuld cease ac- 
cause of intermittent springs. , . 

Spring" Water for Domestic Use. — Potable 

water from springs is generally well adapted for do- 





Fig. 81. 
Another cause of intermittent springs. 

mestic purposes. The chief cause of objection to its 
use is its hardness. Water from fissure springs and 



194 DOMESTIC SCIENCE. 

artesian wells is generally free from surface filth, the 
subterranean supply being deeply set. Good spring 
water is generally clear and well aerated. 

River Water. — The water of rivers usually con- 
tains much mineral matter, and is, in consequence, 
hard ; it is seldom free from organic impurity. This 
contamination is the direct consequence of the drain- 
age exercised by rivers upon the land through which 
they flow. Large quantities of organic filth reach the 
rivers from manured soils ; and in marshy districts the 
running waters are frequently dark from the peaty 
matters dissolved from the ground, in the case of 
large rivers with towns and cities upon their banks, 
vast quantities of sewage are discharged into the 
streams, rendering the water entirely unfit for drink- 
ing or culinary purposes. 

Natural Purification of Running' Water. — it 

is true, certain processes of natural purification are in 
continual operation, and these greatly mitigate the 
contaminating effects above referred to. The atmos- 
pheric oxygen, which freely dissolves in water, unites 
with the products of organic decay there present, and 
thus renders them in time comparatively inert. Run- 
ning water tends, therefore, to purify itself, but the 
completeness with which this will be accomplished de- 
pends upon the amount and the nature of the dissolved 
matters, and the proportion of free oxygen present. 
The extent of this self-purification process is a matter 
of considerable uncertainty. Some chemists have 
asserted that a sewage -laden stream will free itself 
from all impurity in flowing but a few miles, and 



SOURCES OP WATER. 195 

others have as strongly denied the possibility of such 
a thing.* A rapid stream flowing in a stony, precip- 
itous channel, with its waters continually disturbed 
and broken up, and thus more thoroughly exposed to 
the atmospheric action, would be far more rapidly 
purified than would a sluggish stream. 

A Local Example may be cited. The Jordan 
river, flowing past Salt Lake City, received during the 
summer of 1892 considerable of the city sewage, 
owing to the inadequate capacity of the pumping ap- 
paratus at the sewer station. Analyses conducted by 
the author on samples of water taken above and below 
the sewer, showed a great pollution from sewage ; and 
the water of the river did not purify itself to any 
appreciable degree in a flow of 3^ miles. (See chap- 
ter 20.) 

Wells. — In country towns, running streams, which 
have already received attention, and wells, which are 
now to be considered, are the only common sources of 
supply. Surface or shallow wells are usually made by 
digging or boring into the earth till an impermeable 
layer is reached. Upon this the subterranean water 
rests, and the well merely taps the supply. At such 
slight depths the pressure is insufficient to cause the 

* In one of the reports of the English Commissioners on River 
Pollution, it is declared that "the oxidation of the organic matter 
in sewage proceeds with extreme slowness, even when the sew 
age is mixed with a large volume of unpolluted water; and tliat 
it is impossible to say how far such water must flow before the 
sewage matter becomes'thoroughly oxidized. It will be safe to 
infer, however, * * * that there is no river in the United 
Kingdom long enough to effect the destruction of sewage by oxi- 
dation." 



196 DOMESTIC SCIENCE. 

water to rise of itself as from a deep artesian pipe. 
The most of such wells, when new, yield fairly good 
water, hard or soft according to the depth of the shaft 
and the nature of the surrounding soil ; but after a 
short time, the wells become contaminated through 
surface drainage. It is evident that the dangers of 
pollution are greatly diminished in the case of deep 
wells ; the streams that supply these being purified by 
their percolation through the soil. All surface wells 
should be frequently cleansed. The openings should 
be properly protected by curbs and covers, against the 
accidental entrance of foreign bodies. The best of 
wells may be fouled through negligence. 



REVIEW. 

1. What becomes of the water that falls upon the earth from 
the clouds ? 

2. For what properties is rain water remarkable ? 

3. Explain the formation of hillside springs. 

4. Of fissure springs. 

5. Why does water rise through the pipe of an artesian well ? 

6. Describe a demonstration of the rising of water to a com- 
mon level in communicating vessels of different forms and sizes. 

7. Explain capillary attraction. 

8. Describe a simple illustration of water rising to the level 
of its source. 

9. What is an intermittent spring ? ' 

10. Describe a piece of simple apparatus to illustrate a possi- 
ble cause of intermittent springs. 

11. State your opinion as to the cause of intermittent springs. 

12. What do you know as to the purity of river water ? 

13. State what you know of the self-purification of running 
water. 

14. Show the necessity of care in maintaining the cleanliness 
of surface wells. 



WATER, A SOLVENT FOR SOLIDS. 197 



CHAPTER 18. 

WATER, A SOLVENT FOR SOLIDS ', HARDNESS OF WATER. 

Solutions of Solids in Liquids. — Water has been 
called"Nature's universal solvent," and this appella- 
tion is justified by the fact that there are few if any 
substances that can be kept in contact with water 
without yielding something to its dissolving action. 
In undergoing solution in water, the particles of a solid 
body become so separated that the water is uniformly 
diffused among them. In a solution, the solid parti- 
cles are so finely divided and so thoroughly incorpor- 
ated with the liquid that the highest powers of the 
microscope fail to reveal them. The liquid may be 
filtered, but the dissolved solid passes through with 
the menstruum ; and in all physical respects the liquid 
and solid appear as a single substance. 

Solvent Action of Water; Saturated Solu- 
tions. — The solvent power of water toward different 
solids is of varying intensity. Thus, a given quantity 
of water will at ordinary temperatures dissolve five 
times as much sugar as it will alum. When water has 
dissolved of any solid the full amount that it is capa- 
ble of dissolving, the liquid is said to be saturated, 
and the energy of the dissolving action decreases as 
the saturation point is approached. In domestic 
operations the solvent power of water is of very great 
service. Through it we make our pickling brines, 
and prepare sweetened and flavored dishes in great 



198 DOMESTIC SCIENCE. 

variety ; but for it we could not successfully scrub a 
floor, or even wash our hands. 

Effect of Temperature. — The power of water to 
dissolve solids is greatly influenced by changes of tem- 
perature ; as a rule heat increases the energy of solu- 
tion, though to this there are exceptions ; thus, hot 
water will dissolve many times more sugar than will 
cold water ; yet ice water will dissolve twice as much 
lime as will water at a iSoiliug temperature. 

Effect of Finely Dividing" the Solids.— In 

attemping the solution of any solid, the substance 
should be pulverized as finely as possible, as by such 
means much greater surface is exposed to the action of 
the liquid. This may be illustrated by simple means. 
In an experiment, the writer took a lump of rock salt, 
an equal weight of ordinary table salt, and the same 
amount of fine sifted salt. Each of these was placed 
in a vessel by itself ; then an equal quantity of water 
was added to each ; at intervals the vessels were 
shaken, all being subjected as nearly as possible to 
the same degree of agitation. The sifted salt was 
completely dissolve in twenty minutes; the table salt 
had disappeared in forty -three minutes, by which time 
the size of the lump had scarcely diminished ; and 
after five hours part of the rock salt was still undis- 
solved. 

Effect of Agitation. — The solution of a solid 
may be much hastened by frequently agitating the 
mixture, either by shaking or stirring. If the liquid 
be kept at rest, those portions that immediately sur- 
round the solid substance become saturated, and being 



VVATER, A SOLVENT FOR SOLIDS. 199 

thus increased in density they tend to remain at the 
bottom, so that mixture can take place only by the 
slow process of diffusion ; and the unsaturated liquid 
above is kept away from the solid body. In an ex- 
periment to illustrate this, the author took two equal 
quantities of alum. These were placed in separate 
flasks, and to each the same quantity of water was 
added. The contents of one flask were shaken at in- 
tervals ; the other was allowed to remain still. In the 
first vessel the solid was entirely dissolved in three- 
quarters of an hour, while in the second, part of the 
alum still remained solid after twenty-two days. 
Solids Placed in Upper Part of Liquid. — In 

preparing any aqueous solution in large quantity, it 
is well to place the finely divided solid in a basket or 
a bag of coarse material, and suspend this in the upper 
part of the liquid. As the water in contact with the 
solid becomes saturated, its specific gravity is increased, 
and in consequence it sinks, thus giving place to other 
liquid particles. As an illustration of the efficiency of 
this method the following results of experiment are in- 
structive. A weighed quantity of salt was placed in 
an open vessel, and a measured amount of water was 
poured upon it. An equal quantity of salt was sus- 
pended in a cage of wire gauze, just beneath the sur- 
face of a like measure of water in another vessel. In 
the first, a quantity of solid remained undissolved after 
three weeks; in the second, all the solid had disap- 
peared from view in forty -seven minutes. 

Solids dissolved in Natural Waters. — in con- 
sequence of the great solvent energy of water, it is 



•200 



DOMESTIC SCIENCE. 



impossible to find as a natural occurrence a specimen 
of pure water. It will be profitable to consider briefly 
the amount and kind of the solid matters in natural 
waters. The following table shows the amount of 
total solid matter in certain specimens of water, ex- 
pressed in grains of solids per gallon of water. The 
gallon here used is the imperial gallon, equal to 277.27 
cubic inches ; such a gallon of pure water at the tem- 
perature of 62° F. weighs 10 pounds, avordupois, or 
70,000 grains. 

Source. Total solids. Authority, 

(grains per gallon.) 



River Loka, Sweden 
Boston, tJ. S., water works 
Loch Katrine, Scotland 
Schuylkill River at Philadeph 
Detroit River, Michigan . . 
Ohio River at Cinclnnatti 
Loire at Orleans 
Danube, near Vienna 
Lake of Geneva 
River Rhine at Basel 
Thames at London . 
Average of 12 artesian wells 

Provo, Utah 
Salt Lake City supply 
Spring water, Provo, Utah 
Artesian well, near Salt Lake 

City (west) 
Artesi m well, near Salt Lake 

City (soutli) 
Spring, near Salt Lake City 

(south) 
Spring, near Draper, Utah 
Spring, Tooele, Utah 
Jordan River , below Salt Lake 

City* 



0.05 

1.22 

2.H 

4.26 

5.72 

6.74 

9.38 

9.87 

10.64 

11.8 

18.5 

18.6 

16.92 

23.3 

43.27 

23.47 

42.68 
22.16 
24.96 

64.15 



Wells. 

Johnston. 

Wanklyn. 

Johnstjn. 

Johnston. 



Wanklyn, 



The Author. 



♦This large amount of solid matter in the waters of the Jordan 
river consists in great part of organic impurity. As will be seen 
by reference to the table of hardness, (on a subsequent page of 
this chapter) this water is not exceedingly hard. 



W^ATER, A SOLVENT FOR SOLIDS. 



201 



Source. 



Total solids, Authority, 
(grains per gallon.) 



Formation Springs, Idaho 


27.8 


The Author. 


Octagon Spring, at Soda 






Springs, Idaho 


126.66 


<( 


Well water, Gunnison, Utah . 


148.01 


(( 


"Ninety per cent. Spring," at 






Soda Springs, Idaho 


. 198.41 


" 


Warm Springs, Spanish Fork 






Canyon, Utah 


413.72 


" 


Atlantic Ocean .... 


2,688.00 


Wanklyn. 


*SaltLake 


11,777.64 


The Autlior. 


tDead Sea 


17,064.42 


n 



The amounts of solid material as expressed above 
may seem very great, but the actual percentage is 
small ; 10 grains of solids to the imperial gallon 
represents only .014 of 1 per cent, by weight. 

Hardness of Water. — The presence of mineral 
matter in water may impart to the liquid the property 
of hardness, which may be concisely defined as the 



* The water of the Great Salt Lake is subject to great fluctuations 
as regards its contents of solid matter, owing to the variations in 
amount of supply and in the rate of evaporation. In 1849 the lake 
water, according to Dr. Gale, contained 22.282 per cent, of solids; 
that time, however, was one of phenomenally low water, and 
consequently of great concentration. In December, 1885, the 
author found the water to contain 16.7162 per cent, solids, and in 
August, 1889, it held 19.5576 per cent. The mean of these two 
analyses shows 18.1369 per cent., or 11,777.64 grains of solid matter 
per gallon. During the summer of 1892 the waters of the lake 
became still farther concentrated. The average of four analyses 
on different samples collected in September, 1892, showed 14,623.23 
grains of dissolved solids per gallon . 

t Great discrepancy exists among published accounts of the 
solid contents of Dead Sea water. Bernan gives 14,025.48 grains 
per gallon; Captain Lynch collected a sample at a depth of 1110 
feet, and found it to contain 18,902 grains per gallon. The amount 
given above (17,064 grains per gallon) was determined by the 
author in a sample taken from the Dead Sea in April, 1886, by Dr. 
J. M. Tanner, of Logan, Utah. 
7 



202 DOMESTIC SCIENCE. 

power of curdling soap without the formation of a 
lather. The minerals most effectual in causing hard- 
ness are compounds of calcium and magnesium. Salts 
of these unite with the fatty acids* of the soap, form- 
ing insoluble curdy compounds, and all the lime and 
magnesium in the water must be so combined before a 
lather can be produced. A large amount of soap is 
therefore lost so far as any cleansing effect is concerned. 
The hardness of water is usually reckoned in terms of 
this soap destroying power. It has been adopted as a 
rule among chemists, to consider the soap destroying 
effect produced by 1 grain of calcium carbonate in a 
gallon of water as one degree (1°). A water of 10° 
hardness would contain therefore 10 grains calcium 
carbonate per gallon, or the equivalent of this in other 
soap destroying compounds. 

Permanent and Temporary Hardness. — Lime 

carbonate is but slightly soluble in pure water, but 
dissolves readily in water containing carbon dioxide ; 
this gas is present in most natural waters. By boiling 
water so charged, the carbon dioxide is expelled, and 
the lime carbonate being so slightly soluble in the 
water after boiling, falls as a solid precipitate. Look 
inside a much-used tea kettle; there will be found a 



*In a chemical sense, soap is to be regarded as a compound of 
certain alkalies with the acids of fats. The fatty acid in common 
soap is oleic acid; and ordinary hard soap is chiefly sodium 
oleate; soft soap is potassium oleate. In contact with hard 
waters the soap loses its sodium or potassium, these substances 
being replaced by calcium and magnesium; thus, oleates of cal- 
cium and magnesium are produced, which are still soaps, though 
they are insoluble in water, and therefore valueless for lathering 
purposes. (See chapter 36, Part IV.) 



WATER, A SOLVENT FOR SOLIDS. 



203 



heavy deposit of lime salts, as thick scale or incrusta- 
tion. It is plain from this, that by boiling water con- 
taining calcium carbonate in solution, the hardness of 
the liquid may be materially diminished. Hardness 
that is removable by boiling is called teynporary hard- 
ness. Other compounds of calcium, such as the sul- 
phate (gypsum) and the chloride, as also the com- 
pounds of magnesium, impart to the wa,ter permanent 
hardness, which is not removed by simply boiling the 
liquid, because the hardening solids are not thereby 
precipitated from solution. 

Examples of Hardness of Water. — For general 

household purposes, soft waters are the best, though 
for many operations a considerable degree of hardness 
may be tolerated. The following table expresses the 

hardness of several natural waters : 

Degrees of hardness. 



Source. 



Total, 



London Thames 16.5 

Kirby Shore, Westmoreland 25. 
Hillside Spring, Provo,Utah 17. 
Well Water, Gunnison.Utah 6.5 
Average, 9 artesian wells, 

Provo, Utah - 15.2 

Average, 11 artesian wells. 

Salt Lake City - 18.1 

Salt Lake City supply 13.4 

Artesian well, near Salt Lake 

City (west) - 7.4 

Artesian well near Salt Lake 

City (south) - 17.8 

Spring near Salt Lake City 

(south) 
Spring near Draper, Utah 
Spring, Tooele, Utah 
Jordan river, below Salt 

Lake City - 16.5 



Perman- 
ent. 



5 

1.7 



Tem- 
porary. 



12 
4. 



Authority. 
Wanklyn. 



The 



5.4 

10.7 
6.9 

1.2 

7.1 



9.8 

7.4 
6.5 

6.2 

10.7 



14.4 


10.3 


4.1 


13.1 


6.1 


7.0 


18.5 


8.7 


9.8 



Author. 



10.8 



5.7 



204 DOMESTIC SCIENCE. 

It is to be remembered that the hardness of water 
depends largely upon the kind as well as upon the 
amount of solid matter present. The water from Gun- 
nison, Utah, is named in the table on page 201 as 
containing 148.01 grains of solid matter to the gallon ; 
yet this is a relatively soft water, as is seen from the 
table on page 203, which shows for it a total hardness 
of but 6.5°, and of this 4.8° may be removed by 
boiling, leaving a permanent hardness of but 1.7°. 
The solid contents of this water, however, are mostly 
compounds of the alkalies. The water here referred 
to is remarkable in many ways ; its specific gravity is 
high, and though it is constantly used as a potable 
water, its taste is tolerable only to those who have be- 
come accustomed to it. 

Supposed Physiological Effect of Hard 

Water. — The continued use of water that is highly 
impregnated with salts of lime and magnesia is sup- 
posed to be a cause of goitre or hig neck. This dis- 
order is an enlargement of the thyroid gland in the 
neck.* From its prevalence in the limestone regions of 
Derbyshire, England, it is popularly called "Derby- 
shire neck." Most recent investigations lead to the 
belief that the potency of hard waters in producing 
this disorder has been over estimated. Contaminated 



♦Johnston reported that in a jail at Durham, England, all the 
prisoners suffered from neck swelling. An examination of the 
water there used showed that it contained 77 grains of solids per 
gallon, mostly compounds of magnesia and lime. The use of the 
water was then discontinued, a purer kind being substituted, 
containing but 18 grains of solid matter per gallon. The goitrous 
disorder immediately subsided. 



WATER A SOLVENT FOR SOLIDS. 205 

water may favor the disease, but that the use of such 
water is the sole cause can scarcely be credited in the 
light of demonstrated facts. 



REVIEW. 

1. Explain the solvent power of water. 

2. What Is meant by a saturated solution ? 

3. Show the effect of temperature on the rapidity of solution. 

4. Show the effect of finely pulverizing the substance to be 
dissolved. 

5. Show the effect of agitating a liquid in which solution is 
going on. 

6. Why is it best, in preparing a solution of a solid in a 
liquid, to keep the solid near the surface of the liquid ? 

7. What condition of natural waters results from this 
universal solvent power of water ? 

8. Give examples of the amounts of solid matter in different 
waters, local and foreign. 

9. What do you know of the variation of solid contents in the 
water of the Great Salt Lake ? 

10. What is hardness of water ? 

11. How is the hardness of water determined ? 

12. How is hardness of water measured ? 

13. Explain total hardness, permanent hardness, temporary 
hardness. 

14. State what you know of the effect of hard waters on the 
health of the persons using such. 

15. What is goitre ? 



206 DOMESTIC SCIENCE. 



CHAPTER 19. 

WATER, A SOLVENT FOR GASES. 

Air in Water. — The solvent power of water is not 
confined to its action on solids ; gases also may be 
dissolved in large quantities. The commonest gas- 
eous admixtures in ordinary waters are the consti- 
tuents of air. Much good results from such solution 
of air in water; upon the atmospheric gases so held, 
fishes and other aquatic animals depend for respira- 
tion. It is a popular mistake that only land-animals 
breathe air : without this medium of respiration the 
tiniest creature of the sea would die. A living fish 
placed in non- aerated water quickly expires ; and the 
same result follows if the fish be kept in an inadequate 
amount of water, without renewal ; the fish then dies 
from suffocation caused by its own respiratory pro- 
ducts, just as a man shut in a closed room from which 
the gaseous emanations of his body cannot escape, 
will be poisoned by his own breath. A strong ex- 
ample of our subject is found in the growth of the 
tiny coral animals. These belong to the polyp family, 
and are very small and simple in bodily structure. 
They possess the power of extracting the calcareous 
matter from the sea water, and of forming from the 
same a hard, external skeleton, analogous in com- 
position and use to the shells of mollusks, such as 
oysters and snails. Corals usually congregate in 
great numbers, the accumulations of their external 



WATER ITS OCCURRENCE. 207 

skeletons forming coral reefs. Such reefs are found 
only in places that are freely exposed to the action of the 
waves : the little polyps seem to delight in the break- 
ing of the surf, and the whirl of agitated waters. 
Farther, — they are never found living at a great 
depth ; a hundred feet seems to be their limit. These 
peculiarities seem to be due to the animals' need for 
air. In still water, or at a great depth, the coral polyps 
would be deprived of air, in consequence of which 
they could not survive ; but the agitation of the sur- 
face water entangles air sufficient for their use. 

Proportions of Atmospheric Gases in Water. 

— It is remarkable that the atmospheric gases do not 
dissolve in the proportion in which they exist in the 
air. In pure air there will be found about 20.9 per 
cent, of oxygen, and 79.1 per cent, of nitrogen; the 
other constituents need not be considered in this con- 
nection (see page 38). Water that has been fully 
aerated, however, contains the atmospheric gases in 
the proportion of 32 per cent, oxygen and 68 per cent, 
nitrogen. This increased amount of oxygen is of 
great benefit to aquatic animals, the nitrogen, in res- 
piration serving merely as a dilutent.* To drinking 
water, the dissolved air imparts a pleasing and some- 
what pungent taste. This fact may be realized by 

*It has been discovered by Dr. Hayes, " that the water of the 
ocean contains more oxygen near its surface than at a depth of 
one or two hundred feet. This fact has probably some connec- 
tion with the comparative scarcity of animal life at great depths. 
When water is in contact with an atmosphere of mixed gases, it 
dissolves of each a quantity precisely equal to that which it 
would have dissolved if in contact with an atmosphere of this gas 
alone." Wells. 



208 DOMESTIC SCIENCE. 

anyone who, for contrast, will drink for a time water 
from which the air has been expelled by boiling. 

Solvent Power Affected by Temperatupe.— 

Inasmuch as heating water serves to expel its dissolved 
gases, it is plain that a rise of temperature will dimin- 
ish the solvent power of the liquid for gases : this view 
is substantiated by the following facts: Experiment 
has shown that water at 78° C. is able to hold in solu- 
tion 586 times its own volume of dried ammonia gas; 
at 59° C. the water can hold 727 volumes; and at 32° 
C. it may contain 1050 volumes of the gas. A solu- 
tion of ammonia gas in water is sold as " aqua am- 
monia,'' or water ammonia (the common hartshorn of 
the shops). By warming such, large volumes of the 
gas will be given off. 

The ill -smelling gas, hydrogen -sulj^hide, is soluble 
in water; indeed the waters of so-called sulphur 
springs are usually natural solutions of hydrogen 
sulphide. The influence of temperature upon the 
solvent power of water for this gas, is illustrated by 
the following facts : At 78° C. one volume of water 
dissolves 2.66 volumes of hydrogen sulphide; at 59° 
C. water dissolves 3.23 times its own volume of the 
gas: at 32° C. it may hold 4.37 volumes. 

Another gaseous substance commonly found in 
natural waters is carbon dioxide. At 14° C. water 
can hold in solution its own volume of this gas : at 
0° C. it may contain 1.8 volumes. 

Solvent Power Affected by Pressure. — The 

pressure to which liquids are subjected greatly affects 
their power of solution for gases. Thus in the case of 



WATER A SOLVENT FOR GASES. 209 

carbon dioxide, under a pressure of one atmosphere 
(15 lbs. to the square inch), at 14° C. water dissolves 
its own volume of the gas ; under a pressure of two 
atmospheres, (30 lbs. to the square inch) the temper- 
ature being unchanged, two volumes may be absorbed, 
and so on ; within certain limits the solvent power is 
directly proportional to the pressure. 

Soda Water. — An aqueous solution of carbon 
dioxide constitutes the so-called soda water. By the 
action of some mineral acid (usually sulphuric acid) 
on sodium bicarbonate, chalk, or marble dust, carbon 
dioxide is generated in great quantity ; the gas is 
conducted into a stout closed vessel containing water; 
as the gas accumulates, the pressure increases ; and at 
the same time the water being kept violently agitated, 
the gas passes into solution. It will be held captive 
by the water, however, only as long as the pressure 
continues ; as soon as the liquid is drawn from the 
holder, the gas escapes giving the effervescent and 
pungent qualities which are sought.* 

*The question of the wholesomeness of soda water has excited 
some general interest. The presence of small quantities of car- 
bonated water in the stomach seems to produce pleasing- and ex- 
hilarating effects; and if the preparation be pure, it is difficult to 
see what harm is likely to result from its moderate use. Some 
soda-water makers are not careful to vise pure water; and are 
indifferent to the cleanliness of their apparatus. It is possible 
too, that metallic compounds may result from combinations with 
the material of the holders and pipes. The admixture of flavor- 
ing syrups is objectionable for the reason that the purity of such 
preparations cannot be relied on, and the coloring matters used 
to impart the deceptive tints to strawberry, raspberry, black- 
berry, and other syrups, are frequently of "a deleterious kind; and 
farther, the habitual taking into the system of large quantities of 
saccharine material is certainly injurious to health. 



210 DOMESTIC SCIENCE. 

There are many natural occurrences of carbonated 
waters : to such class belong the springs of Saratoga, 
New York, and Seltzer, Germany, as also many local 
springs. (See chapter 23.) From such springs are 
taken the so-called natural soda waters, "Seltzer," 
"Vichy," " Appolinaris," and "Congress." 

Injurious Gases Absorbed by Water. — The 

fact of the readiness with which gases dissolve in 
water, should restrain us from using for drinking pur- 
poses, water that has stood long in open vessels. 
Water that has been exposed, even for an hour or two, 
to the air of a closed room, will be found to be 
charged with the gases of the apartment ; and these 
may be of the most deleterious kind. In the treat- 
ment of the sick, precautions are necessary that the 
patients drink not of any liquids that have been long 
exposed to the air of the room. 



REVIEW. 

1. Prove that air exists in water in a state of solution. 

2. Of what use is the air dissolved in water ? 

3. Explain some of the conditions under which coral polyps 
grow. 

4. What do you know of the proportion in which the most 
abundant atmospheric gases dissolve in water ? 

5. Explain the effect of a varying temperature on the solvent 
power of liquids for gases. 

6. Illustrate the power of water at different temperatures to 
dissolve ammonia gas. 

7. Hydrogen- sulphide. 

8. Carbon dioxide. 



WATER A SOLVENT FOR GASES. 211 

9. Explain the effect of pressure on the solvent powers of 
liquids for gases. 

10. How is the so-called soda water produced ? 

11. What is your opinion as to the wholesomeness of "soda 
water?" 

12. Show the danger attending the drinking of liquids that 
have been exposed to impure air. 



212 DOMESTIC SCIENCE. 



CHAPTER 20. 

ORGANIC IMPURITIES IN WATER. 

Organic Impurities Deleterious. — The impuri- 
ties most to be feared in water that is used for domestic 
purposes are of an organic nature, ^ — that is, they are 
products of vegetable and animal decay. An average 
amount of mineral impurities need not render water 
at all unfit for use. A water containing less than 15 
grains of calcium salts to the gallon is usually consid- 
ered good ; and 20 grains of such solids to the gallon 
is not an unusual amount ; but a very small amount of 
organic impurity may render the water unsafe for 
drinking purposes. 

Nitrogenous Impurities in Water. — Organic 

matters containing nitrogen are most deleterious. It 
is common with chemists to determine this organic im- 
purity in the form of ammonia, it being possible to 
convert such nitrogenous matters into ammonia, and 
to determine the amount present with fair accurary. 
The ammonia present in waters as a result of decay 
that has already taken place is determined as free am- 
monia ; the rest of the nitrogenous organic matter, 
which may be decomposed and converted into ammonia 
by the analytical process, is called albuminoid ammonia. 
Regarding the amounts of these matters allowable in 
drinking water according to the established standard 
of safety, Mr. Wanklyn of England, a generally rec- 



ORGANIC IMPURITIES IN WATER. 



213 



ognized authority upon this subject, has said: "I 
should be inclined to regard with some suspicion a 
water yielding a considerable quantity of free am- 
monia, along with 0.05 parts of albuminoid ammonia 
per million. * * * Albuminoid ammonia above 
0.10 per million begins to be a very suspicious sign, 
and over 0.15 ought to condemn a water absolutely." 
Below are exhibited the results of some analyses of 
natural waters : 



Parts per million. 





Free 


Albuminoid 




Source. ammonia. 


ammonia. 


Authority. 


Town water, Manchester, 








England 


.01 


.06 J. 


A. Wanklyn. 


Glasgow, Scotland, Loch 








Katrine 


.00 


.08 


<( 


London Thames, at high 








tide 


1.02 


.59 


" 


Emigration Canyon stream. 








Salt Lake valley 


.046 


.045 J. ' 


r. Kingsbury. 


Red Butte Canyon stream 


.028 


.120 


<( 


Parley's Canyon stream 


.010 


.060 


<< 


Average 10 artesian wells. 








Provo City, Utah 


2.11 


.18 The Author. 


Average 16 surface wells, 








Provo City, Utah 


.125 


.284 




In-doors pump, Provo City, 








Utah 


0.73 


5.40 




Artesian well, Spanish 








Fork, Utah 


.72 


5.18 




Average 13 artesian wells. 








Salt Lake City, Utah 


.669 


.22 




Surface well, Salt Lake City 


3.28 


.34 




City water mains. Salt 








Lake City 


.13 


.052 




Artesian well, (B) near Salt 








Lake City (west)* 


6.4 


.076 




Artesian well (C) near Salt 








Lake City (west) 


0.74 


.004 





214 DOMESTIC SCIENCE. 

Parts per million. 





Free 


Source. 


ammonia. 


Artesian well near Salt Lake 




City (south) 


7.051 


Spring near Salt Lake City 




(south) 


0.084 


Spring, near Draper, Utah 


0.211 


Spring, Tooele, Utah 


1.96 



Albuminoid 
ammonia. Authority. 

.045 The Author. 

.017 
.171 
2.65 •' 

Chlorine in Water. — Associated with organic im- 
purity of the kind described, water may contain large 
quantities of chlorine, usually combined with sodium 
as common salt, or with other alkaline metals as 
chlorides. These compounds may result from the 
presence of sewage filth or drainage from cess-pools ; 
though the discovery of chlorine in water, unaccom- 
panied by organic impurity, is not of such serious 
import. 

The following table will convey an idea of the vary- 
ing amounts of chlorine in different waters. The 



*It will be observed that many of the ai'tesian waters of which 
analytical results are given' in the text, show excessive 
amounts of nitrogenous impurity. Such contamination, how- 
ever, is far less dangerous than it would be if occurring in surface 
water, for, as stated, (page 216) it is not the dissolved organic 
matter itself that constitutes the source of danger in waters so 
polluted, but the occurrence of living organisms and germs of 
disease which are nourished by the organic filth. Waters spring- 
ing from deep sources are less likely to be infested with such or- 
ganisms; and during the prevalence of communicable diseases in 
any place, I would rather drink artesian water, though compar- 
atively rich in dissolved organic matter, than surface water of 
greater chemical purity, but which had been exposed to infection 
from surface filth. Though chemical analyses are invaluable in 
demonstrating the fitness or the unfitness of water for domestic 
use, such analyses do not tell the whole story. 



ORGANIC IMPURITIES IN WATER. 



215 



specifications are given in grains per imperial gallon of 
70,000 grains : 



Source. 

Bala Lake, Wales 
Thames at Loudon 
Average 22 surface wells, 

Provo City, Utah 
Average 8 artesian wells, 

Provo City, Utah 
Average 8 artesian wells, 

Salt Lake City, Utah 
Artesian well CB) near Salt 

Lake City (west) 
Artesian well (C) near Salt 

Lake City (west) 
Artesian well near Salt Lake 

City (south) 
Spring near Salt Lake City 

(south) 
Spring near Draper, Utah 
Spring, Tooele, Utah 
Jordan river. Salt Lake City, 

150 yards above sewer 
Jordan river, Salt Lake City, 

150 yards below sewer 
Surface spring, Provo City 
Artesian well, Spanish Fork, 

Utah 
Salt Lake City supply 



Chlorine. 
Grains per gallon. 
0.7 
1.2 

1.22 

2.029 

3.688 

1.092 

.435 

.205 

.629 
.239 
.205 

1.400 

1.598* 
.977 

.992 

.87 



Authority. 
Wanklyn. 

The Author. 



* The Jordan river water just above the Salt Lake City sewer 
shows 1.4 grains per gallon of chlorine ; below the sewer the water 
holds 1.598 grains per gallon. The increase, .198 grain per gallon 
mpst have been derived almost wholly from the effluent sewage; 
and this amount represents more real danger to the users of the 
water than does the large amount contained in the water above 
the sewer: for all the natural waters of the Salt Lake valley are 
rich in dissolved chlorine, mainly from the common salt and 
other alkaline chlorides washed from the soil. Chlorine in water, 
known to be derived from foul sources, threatens danger through 
the probable association of disease germs. 



216 DOMESTIC SCIENCE. 

Real Dang'er from Org'anic Impurity. — The 
presence of small amounts of organic matter would 
not of itself prove a source of injury to health. The 
danger lies in the fact that living organisms flourish in 
water so contaminated, and these may be of an injur- 
ious type, since many forms of contagious disease 
have been proved to be associated with the existence of 
such organisms within the system. The germs of 
cholera, small-pox, and many forms of fevers, thrive 
in water that is organically impure. Dr. Cyrus Ed- 
son, the well known sanitary chemist of New York, 
has declared his belief that ninety-nine per cent, of 
cholera cases are propagated through the medium of 
drinking water. The reports of the sanitary officials 
in India show a close relationship between the epidemic 
outbursts of cholera, to which that country has been 
frequently subject, and the use of polluted drinking 
water. Enteric or typhoid fever is more frequently 
spread by the use of contaminated water than in any 
other way.* 

Dysenteric Affections from Impure Water. 

— Dysenteric and diarrhcjeal affections »re in many 
cases directly traceable to polluted water. The sample 
named "In -doors pump, Provo City, Utah," in table 

* In referring to typhoid fever as a result of the use of water 
contaminated with filth, Drs. Huxh y and Youmans say: "The 
instances of its originating in this way are too numerous, and 
have been too clearly traced to admit of a doubt of the fact; nor 
does mere dilution of the poison remove the danger as the follow- 
ing will show: A recent outbreak in an English town was traced 
to the milk with which numerous families were served, and it 
was conclusively proved that the milk was poisoned by being 
stored in cans that had been washed with water contaminated 
with sewage from an imperfect drain." 



ORGANIC IMPURITIES IN WATER. 217 

on page 213, was taken from a well, provided with a 
curb and a drainage pipe. The water was used in a 
large boarding house, and the fact was reported that 
severe dysentery was common among the inmates. An 
examination of the well was made, and the drain -pipe 
was found to be completely choked, so that the foul 
wastes made their way back to the well, and this re- 
pulsive mixture was drunk. The pipe was cleared, the 
well thoroughly cleansed, and the derangements in the 
health of the inmates straightway disappeared. 

Diarrhoea Caused by Foul Water.— Mr. Wank- 

lyn, the English analyst, examined water from a well 
at the Leek Workhouse, and found it to contain .02 
parts of free ammonia, and .34 parts of albuminoid 
ammonia per million of water. Of this occurrence he 
says, "In the Leek Workhouse there has been for 
years past a general tendency to diarrhoea, which 
could not be accounted for until the water was exam- 
ined and shown to be loaded with vegetable matter." 
He adds, "A well on Biddulph Moor, a few miles from 
Leek, yielded .05 grain chlorine per gallon, and .03 
free, and .14 albuminoid ammonia per million. The 
persons who were in the habit of drinking this water 
suffered from diarrhoea."* 



♦"Dissolved or suspended organic matter, whether of vegetable 
or animal origin, will cause diarrhoea. In the recent war, great 
numbers of cases occurred from the use of marsh or ditch water; 
the sickness ceased when wells were sunk." 

"Mineral matters, either dissolved or suspended, will give rise 
to it if present in considerable quantity." 

"Water impregnated with nitrate of lime will produce diarr- 
hoea. Brackish water will act in the same way." 

Huxley & Youmans, 



218 



DOMESTIC SCILNCE. 



Suspended Matters in Well Waters. — Well 

waters are often contaminated by the entrance of for- 
eign matters because the openings are not sufficiently 
protected. The author has examined many specimens 
of water from wells so exposed, and is convinced that 
reckless carelessness exists as to protecting the wells 
from dust, and the like. Nearly one-third of the 




Fig. 82. 
Suspended matters in well waters. 

waters so examined have been found to contain sus- 
pended particles, which, under the microscope, reveal 
themselves (figure 82) as partly decayed fibres of 
straw ; cotton ; wool (c) ; hair (e) ; pollen grains from 
plants (5) ; spores of fungi ; scales of butterflies and 
moths (a). Dr. Parkes, of London, referring to the 
results of his examinations of water in that great city, 
says, '^ Fibres of cotton, wool, or linen, starch cells 



ORGANIC IMPURITIES IN WATER. 219 

(figure 82, f) macerated paper, human hairs, yellow 
globular masses, and striped muscular fibre (undi- 
gested meat) ((^), with squamous epithelium cells, are 
all indicative of contamination of the water with hu- 
man refuse, and most probably with sewage." 

Living Organisms in Water. — ' 'Amongst these 




Fig. 83. 
Living organisms in potable waters. 

matters andfeeding on them," continues Parkes, ''will 
probably be found living organisms of low types, such 
as bacteria (micrococci, bacilli, and vibriones), amoe- 
bae and infusoria. These organisms are not in them- 
selves dangerous, but they indicate the presence of 
matters, chiefly organic, upon which they feed, and 
amongst them may be those germ-producing organisms 
which so often find their way into sewage." The ac- 



220 DOMESTIC SCIENCE. 

companying sketch (figure 83) shows a few of the 
living organisms reported as having been found in 
potable waters ; a, represents a species of green mold 
(penecillium) ; h, another form of mold (mucor) ; d, 
a fungus (aspergillus) ; e and/, forms of bacteria (mic- 
rococcus, bacillus, and vibrio) ; c, a simple form of ani- 
mal belonging to the protozoans (vorticella) ; g, 
another protozoan (paramecium). 



REVIEW. 

1. Which are the most injurious of the ordinary impurities of 
potable waters? 

2. State what you know of the average amounts of mineral 
impurities ordinarily allowable in water used for drinking. 

3. What is organic matter? 

4. In what forms is the organic impurity of water usually de- 
termined in chemical analysis? 

5. What do you know of the opinions of chemists as to the 
limits of organic impurity ordinarily allowable in potable waters? 

6. Give instances, principally local, of the occurrence of or- 
ganic impurity in water. 

7. What do you know of the significance of chlorine in 
water? 

8. Give instances of the amount of chlorine occurring in dif- 
ferent waters. 

9. Wherein lies the danger of organic contamination of 
water? 

10. Give known instances of bodily disorders resulting from 
the use of water so contaminated. 

11. What do you know of the possibility of disseminating ty- 
phoid fever through the medium of foul water? 

12. Enumerate some of the mechanically suspended impurities 
to be found in exposed waters. 

13. What do you know of the occurrence of living organisms 
in water? 



SIMPLE TESTS FOR WATER. 221 



CHAPTER 21. 

SIMPLE TESTS FOR PURITY IN POTABLE WATER. 

Chemical Analysis of Water. — in cases of sus- 
pected water contamination, a sample should be sub- 
mitted to a competent chemist for analysis. He will 
certify to the state of purity in the sample, and as to 
the possibility of bettering the water by any simple 
means. From him the following items of information 
should be asked : 

1. The total amount of solid matters present. 

2. The nature of the dissolved solids. If possible a 
full analysis of the solids should be made, and in all 
cases the predominating metals should be determined, 
and the nature of the prevailing salts, whether carbon- 
ates, sulphates, or chlorides. 

3. The degrees of hardness, expressed as total hard- 
ness, temporary hardness, and permanent hardness. 

4. The amount of chlorine present. 

5. The amount of nitrogenous organic matter de- 
termined as free ammonia and albuminoid ammonia. 

6. The presence or absence of deleterious gases. 

7. The presence or absence of poisonous metals. 

8. The nature of the mechanically suspended mat- 
ters. 

Tests of Purity in Water. — From such facts, 

the general condition of the water can be inferred. 



222 DOMESTIC SCIENCE. 

However, it is not always possible to secure the aid of 
chemical skill in examining drinking water ; it is 
proper therefore that we become acquainted with at 
least a few of the determinative tests to which water 
can be subjected. The following observations may be 
made by any one with practice and scrupulous care, 
and by such assistance much reliable information as to 
the purity of any water may be gained. 

1. Color. It is a common statement that pure water 
is colorless ; this, however, is strictly true of small 
bodies of water only ; for when viewed through great 
depths, the purest of water possesses a distinctly 
bluish tint. To determine the color of a potable 
water, fill with the sample a tall cylinder or bottle of 
clear white glass ; cylinders made for the purpose, 
about two feet in length are best adapted. Place the 
vessel on a white dish, or a sheet of white paper, and 
carefully examine, looking from the surface downward. 
Good waters will show the bluish tint above referred 
to ; any large amount of vegetable impurity will give 
a greenish color ; and sewage filth will tint the water 
yellow or light brown. If salts of iron are present in 
the water, the last named indication will be unreliable, 
as such salts themselves would give to the water a 
brownish hue. 

2. Clearness. Examine as for color ; also hold the 
vessel containing the sample toward the light ; then 
view it when held before some black object. Any tur- 
bidity is an indication of the presence of organic im- 
purities in solution, or of suspended solid matters. All 
turbidity is a sign of contamination, though the op- 



SIMPLE TESTS FOR WATER. 223 

posite must not be inferred — that clear water is neces- 
sarily pure. There is a wide -spread popular error 
on this point, and it has led to the use of very foul 
waters because of their sparkling appearance. One of 
the clearest waters ever examined by the writer, was 
taken from a pump in Greenwood Cemetery, Brooklyn, 
N. Y.,* yet it was found to be heavily laden with 
nitrates, which, doubtless, were derived from the 
bodies there entombed.! 

3. The Odor of drinking water is an important 

* A number of pumps are to be found in that wonderful and 
beautiful city of the dead, and I have looked with horror upon 
visitors drinking from these grave-fed wells. Such water is 
highly charged with the nitrates and nitrites of decomposing 
flesh, and water so impregnated has a cooling, saline taste, very 
pleasant to the palate of the blissfully ignorant drinker, and sure 
to excite subsequent thirst, which will lead to continued draughts. 
During another visit to Greenwood in the summer of 1889, 1 was 
glad to see that a notice had been placed over each of the pumps, 
stating that the water was to be used for irrigating the flower 
beds only: but the pumps are still there with the levers free, and 
visitors continue to drink at them. Should we marvel that the 
silent metropolis is so well tenanted? 

fThe London i^awce^ in referring to water so contaminated, says: 
" It is a well ascertained fact, that the surest carrier and the most 
deadly fruitful nidus of zymotic contagion, is this brilliant, entic- 
ing-looking water, charged with the nitrates which result from 
decomposition." 

Johnston says of such waters: " The water of a well close to 
the old churchyard on the top of Highgate Hill was examined by 
the late Mr. Noad, and found to contain as much as 100 grains of 
solid matter lo the gallon, 57 grains of which consisted of the 
nitrates of lime and magnesia. This large amount of nitrates is 
traced to the neighboring graveyard, as such compounds are 
generally produced where animal matters decay in porous soils. 
* * * While the buried bodies were more recent, animal mat- 
ter? of a more disagreeable kind would probably have been found 
in the well, as I have myself found them in the water of wells 
situated in the neighborhood of farm-yards." 



224 DOMESTIC SCIENCE. 

characteristic. To determine it, procure a quart bottle ; 
see that it is clean and provided with a well -fitting- 
cork. Half fill the bottle with the water under ex- 
amination ; cork the vessel and set it aside in a warm 
place for a few hours ; then shake it well, open and 
smell. Any perceptible odor should condemn the 
water for domestic use until a determinative analysis 
has been made. If no odor is perceptible after gentle 
warming, the water should be heated nearly to boiling, 
the odor being tested at frequent intervals as the heat- 
ing proceeds. Remember that pure water is odorless. 

4. Taste. Water intended for household use should 
be entirely devoid of taste. Any perceptible flavor 
should be considered as strong evidence that the 
liquid is contaminated, and chemical tests should be 
employed. As many mineral ingredients impart but a 
feeble taste to water, these tests must be made with 
critical care. Many waters that seem tasteless while 
cold develop a positive taste if gently warmed. Do 
not consider the flat insipid nature which all ordinary 
water acquires by boiling, as a proof of contamination. 

5. The presence or absence of Chlorine should be 
next determined. This can be satisfactorily done by a 
competent chemist only, though the method of pro- 
ceeding is simple. A drop of pure nitric acid and a 
few drops of clear silver nitrate solution are to be 
added to the water under test. A milkiness or turbidity 
is due to the formation of silver chloride, and is a proof 
of the presence of chlorine, in the sample. As was 
stated on page 214, the presence of chlorine in mod- 



SIMPLE TESTS FOR WATER. 225 

erate quantity is a sign of danger only when associated 
with organic matter. 

6. The presence of Organic Matter in water is diffi- 
cult to determine, except by complicated chemical tests. 
Yet such determination is of utmost importance in 
deciding upon the wholesomeness of water. Much 
information upon this point, however, may be gained 
from the tests on color, odor, and taste as before de- 
scribed. Heisch's test for organic impurity in water 
maybe made as follows: ^'Fill a clean pint bottle 
three-fourths full of water; dissolve a teaspoonful of 
loaf or granulated sugar ; cork the bottle and set it in 
a warm place for two days. If the water becomes 
cloudy or muddy it is unfit for domestic use. If it 
remain perfectly clear it is probably safe to use." Some 
waters contain so much organic filth that when 
boiled the polluting substances coagulate, as does the 
white of an egg when heated ; when the water cools 
the impurities separate in fiocks. • 



REVIEW. 

1. What are the chief chemical data on which to base an 
opinion as to the wholesomeness of any sample of water? 

2. State the significance of color in water. 

3. How would you examine a sample of water to ascertain its 
color? 

4. What is the significance of clearness of potable water? 

5. Show that clear water is not necessarily pure. 

6. Explain the significance of odor in drinking water. 

7. Give details of testing a sample of water for odor. 

8. Show the significance of taste in potable water. 

9. How may water be tested for chlorine? 
10, For organic impurities? 



226 DOMESTIC SCIENCE. 



CHAPTER 22. 



PURIFICATION OF WATER. 



The fact that water becomes so readily contam- 
inated with both organic and inorganic impurities, 
gives great importance to the subject of water purifi- 
cation. Many methods of improving the qualities by 
simple treatment have been proposed and practiced. 

Purification by Boiling*.— For operating on a 
small scale, as for domestic purposes, boiling has long 
been in favor. This treatment may produce import- 
ant changes in potable water. For example, consider 
a specimen of water possessing great temporary hard- 
ness, and moderately contaminated with organic re- 
fuse. As the boiling proceeds, the dissolved gases of 
the water, among them the carbon dioxide, which is 
sure to be present in such a sample, will be expelled ; 
the lime carbonate, from which the water derived its 
quality of temporary hardness will separate from solu- 
tion, and fall as a sediment, leaving the water com- 
paratively soft. This is the easiest and the cheapest 
known method of softening on a small scale such lime- 
carbonate waters. 

Another probable result of the boiling will be the 
coagulation and consequent separation of certain 
forms of organic matter. Farther than this, the boil- 
ing temperature will kill many if not all of the living 



PURIFICATION OF WATER. 227 

germs present in the water, thus insuring the liquid 
against the power of communicating specific diseases. 
Much discussion has arisen among scientists as to the 
minimum temperature that is fatal to the common 
forms of bacterial life, and from the facts adduced by 
the controversy we may conclude that the temperature 
of 212° F. will effectually destroy all living organisms 
found in water, except possibly the spores of certain 
bacteria, and these may be surely killed by boiling the 
water several times at intervals, allowing time between 
the boilings for the spores to develop. Parkes de- 
clares his belief that there is scarcely any doubt that 
the specific poisons of cholera, enteric fever, and other 
forms of contagion such as are commonly propagated 
through the medium of impure drinking water, are 
destroyed with certainty by even a few minutes' boil- 
ing. It must be remembered however, that at great 
altitudes water boils at a temperature considerably 
below 212° F. Under such conditions of diminished 
heat, the certainty of destroying microscopic organ- 
isms by boiling the water is considerably lessened. 

Boiled water possesses an insipidity which, to many 
people, is almost nauseating; this taste is due to the 
non -aerated condition of the water, the atmospheric 
gases having been expelled by the heat. Such water 
may be again aerated by allowing it to flow slowly from 
a perforated cask, or through a collander, in many 
fine streams. 

Purification by Distillation. — Distillation is the 

means by which the purest water may be obtained. 
The process consists in boiling the water, and in col- 



228 



DOMESTIC SCIENCE. 



lecting and condensing the steam. In this way the 
solid ingredients are left in the boiler. The greater 
part of the dissolved gases will be carried off in the 
first part of the distillate; if this portion be rejected, 
the water that subsequently distills may be regarded 
as approximately pure. 

The apparatus for distillation (figure 84) consists of 




Fig. 84. 
Apparatus for distillation of water. 

a boiler A, with a delivery pipe B and C through which 
the steam is conducted to a spiral tube or worm set in a 
vessel of cold water S ; within the spiral tube, the steam 
condenses to the liquid state, and this water is caught, 
in a suitable vessel. A stream of cold water is sup- 
plied to the condenser through an inlet tube, the surplus 
being carried off through an exit pipe. 



rURIFICATION OF WATER. 229 

For the distillation of water or other liquids on a 
small scale, the apparatus represented in figure 85 may 
be employed. In addition to its portability this has 
the advantage of being constructed in all its essential 
parts of glass. In the sketch A is a glass flask, con- 
taining water, and heated by a spirit lamp placed below ; 
B is a delivery tube connected with the condenser C. 
^^^^_^ This form of condenser 
rr^^^^^^l^ il is called from its inven- 
({^ \ <K I ^ tor theLiebigcondenser ; 

fW. ,7 I ,..., ^^ it consists of a central 

%[^^ // A 9 tube continuous with B, 

,/ ^^^1 ajj(^ surrounded by a 

Fiff 85 

Portable distillation apparatus of large outer tube, through 
glass. which cold water is 

flowing. The central tube is thus incased in a water 
jacket, a continuous supply being made through D, 
an escape is provided through E, The distillate is 
caught in F. 

Great care should be exercised that the distilling 
apparatus be clean, and of such material that the water 
will not dissolve appreciable amounts of its substance. 
Houses that are furnished with steam heating appliances 
may be easily supplied with a sufficiency of distilled 
water. Water that has been distilled with all proper 
precautions may be considered free from all disease 
germs, and therefore comparatively safe for domestic 
use. Before such water can be relished for drinking 
purposes it must be aerated, and this may be accom- 
plished by the same means as are employed to aerate 
boiled water. 



230 DOMESTIC SCIENCE. 

FiltPation is often resorted to as a purifying pro- 
cess. Many forms of domestic filters are now in the 
market. The manufacturers of these devices usually 
guarantee them to free the water from all suspended 
and dissolved matters ; but such extravagant claims 
are seldom realized in practice. The commonest form 
of water filter consists of a vessel of wood, stone, or 
metal, containing a slab of porous earthenware, and 
layers of charcoal, magnetic iron oxide, and gravel ; 
in some filters pounded glass and sponge are used. 
Through this the water is allowed to percolate, thus 
imitating in a feeble way the grand processes of nat- 
ural filtration in which foul waters become sweet by 
percolating through the porous strata of the earth, 
A filter which in service will prove fully as efficient as 
many of the high-priced articles offered in the market, 
may be made as follows : Provide some water-tight box, 
cask or jar of convenient size ; bore a number of holes 
in the bottom of the receptacle, and place within it 
alternate layers of recently heated charcoal, fine gravel, 
and sand, till it is half or two -thirds full. Pour in at 
the top the water to be filtered ; that which first passes 
through may be somewhat turbid, from loose particles 
derived from the filter ; return such to the top. In a 
short time the filtered water will appear perfectly 
clear, though it may have been originally of the foulest 
kind. Such a filter is of service as long as it is clean. 
The great objection to the use of domestic filters is 
based upon the exceedingly small amount of filtering 
material, and the consequent rapidity with which the 
filters become choked. A dirty filter — one that has 



PURIFICATION OF WATER. 231 

taken from the water all the foul matter that it is 
capable of removing — is a source of pollution to the 
water that subsequently passes through. 

The process of filtration is a serviceable one, and 
could it be successfully performed with an apparatus 
of adequate size, it would be regarded as a very 
efficient aid in the purification of water. The writer 
has examined many forms of household filters, and has 
analyzed samples of water both before and after filtra- 
tion through such ; and he is convinced that most of 
the filtering devices require for cleanliness far more care 
and attention than the ordinary house-keeper is in- 
clined to bestow upon them. And if not cared for, 
they become sources of positive danger. 

A domestic filter of recent invention and one of the 
best yet offered , is the Pasteur- Chamberkmd device. In 
this the water is forced through several partitions of 
porous earthenware, by which treatment it is entirely 
freed from bacterial organisms. Water filtered in this 
apparatus is completely sterilized, though its dissolved 
solids are not diminished. Difficulty is experienced in 
cleaning this filter. 

A filter, even when working in the best manner 
possible, cannot separate from water its dissolved 
matters ; charcoal, it is true, will take out some portion 
of the ammonia and other gases, but the removal of 
these is in no case complete, and the amount of dis- 
solved solids is in no way diminished by filtration. 

Filtration on a Large Scale. — For the removal 

of mechanically suspended matters, such as clay, mud, 
and sand, the filtration process proves of great service; 



232 DOMESTIC SCIENCE. 

and in the purification of water on a large scale, as for 
a city supply, filtration is an indispensable part of the 
treatment. The water of London is filtered by being 
passed through beds of sand and gravel. The average 
thickness of the sand layers is three feet; beneath this 
are strata of gravel, the coarseness increasing with the 
depth. The water upon the filter beds is never allowed 
to exceed two feet in depth. In practice it is found 
necessary to frequently renew the upper layers ; the 
rapidity with which the filters become choked is sur- 
prising. 

Chemicals as Purifying" Ag'ents.— it is claimed 

that certain chemical substances when added to water 
exert a purifying effect upon it. Of these Alum is 
perhaps in commonest use. When mixed with certain 
waters, alum forms a bulky, gelatinous precipitate of 
aluminium hydrate, which in settling carries with it 
much of the matter held in mechanical suspension. 
Good authorities recommend about six grains of alum 
to the gallon of water as the best proportion. The 
waters of the Seine are used in Paris after clarification 
by this simple process.* 

*" For household use, on a small scale, water can be easily clar- 
ified and purified by placing a layer of clean cotton two or three 
inches deep at the bottom of a glass percolator, such as is used 
by druggists, and pouring the water to be filtered, to which the 
solution of alum has been added, into the percolator, and allowing 
it to drip through into a clean vessel placed to receive it. The alum 
solution is conveniently made by dissolving half an ounce of alum 
in a quart of water, and of this solution a scant teaspoonful should 
be added to each gallon of water to be filtered. Alum is now used 
in a number of filtering and purifying systems which have of late 
years been brought prominently before the public by their invent- 
ors or the companies controlling them." — Dr. W. G. Tucker, in Science, 
July 15th, 1892. 



PURIFICATION OF WATER. 233 

Tannin exerts a coagulating effect upon certain 
forms of organic matter. The common wa}- of add- 
ing the tannin is to place oak chips in the water, this 
kind of wood being very rich in the astringent named. 
This treatment is of use only if the polluting ingredi- 
ents be of an albuminoid character ; but in waters so 
contaminated the method is a very serviceable one, as 
the coagulum in forming entangles most of the other 
impurities. 

Prof. Johnston states that the marshy waters of 
India are rendered potable by the use of a nut — strych- 
nos potatorum. The powder produced by crushing 
the nut is rubbed on the inside of the water vessel, and 
the impurities of the liquid soon subside. The same 
authority reports that in Egypt the muddy water of 
the Nile is clarified by the addition of bitter almonds.* 

Softening" Hard Waters. — For softening waters 
possessing a high degree of temporary hardness, the 
value of the boiling process has been already pointed 
out. This mode of treatment, however, is inapplica- 
ble on a large scale ; and a much cheaper method has 
been devised. This is known as Clark's process ; it 



*It is well to read here the experience of the Israelites— Exodus 
XV, 23-25: 

"And when they came to Marah, they could not drink of the 
waters of Marah, for they were bitter: therefore the name of it 
was called Marah. 

"And the people murmured against Moses, saying, What shall 
we drink? 

"And he cried unto the Lord: and the Lord showed him a tree, 
which when he had cast into the waters, the waters were made 
sw^eet; there he made for them a statute and an ordinance, and 
there he proved them." 



234 DOMESTIC SCIENCE. 

consists in adding lime water to the water that is to be 
softened. It may appear to be a strange proceeding, 
to add lime for the purpose of removing a compound 
of lime, yet the explanation of the operation is simple. 
As already explained, it is mostly lime carbonate that 
gives to water the property of temporary hardness ; 
and this substance is scarcely soluble at all in pure 
water ; but it dissolves with ease in water containing 
carbon dioxide. Now the lime that is added to such a 
carbonated water will unite with the free carbon diox- 
ide there present, forming with it insoluble lime car- 
bonate ; at the same time the carbonate originally in 
solution will fall as a sediment because the removal of 
the free carbon dioxide robs it of its solvent. In this 
way it is possible to reduce the hardness of water 70 
or 80 per cent. The addition of the lime water causes 
a turbidity throughout the liquid, and time must be 
allowed for the sediment to subside before the water 
can be used. In Porter's modification of Clark's pro- 
cess, the water is filtered under pressure, the solid 
particles being thus more speedily removed. 



REVIEW. 

1. Name the principal methods of artificially purifying 
water, 

2. Show the effects of boiling in improving the quality of 
water. 

3. Explain the insipidity of boiled water. 

4. What is distillation ? 

5. Describe the process of distilling water on a large scale. 



PURIFICATION OF WATER. 235 

6. Describe the Liebig condenser and its attachments for dis- 
tillations on a small scale. 

7. What do you know of filtration of water as a purification 
process ? 

8. Describe an ordinary domestic filter. 

9. Describe the Pasteur-Chamberland filter. 

10. Show the imperative need of keeping a domestic filter 
clean. 

11. Explain Clark's process of softening waters. 

12. Explain Porter's modification of this process. 

13. Name the principal chemical substances known to exert a 
purifying effect on water, 

14. Explain the effect of alum . Of tannin. 



236 DOMESTIC SCIKNCE. 



CHAPTER 23. 

MINERAL WATERS. 

Classification of Mineral Waters. — The term 

mineral water is applied to any natural water that con- 
tains so large a proportion of mineral ingredients as to 
derive therefrom a characteristic taste. No clear dis- 
tinction, other than this, exists between potable and 
mineral waters. According to their prevailing ingre- 
dients, mineral waters are usually classified as sulphur 
waters, carbonated waters, chalybeate waters, alum 
waters, siliceous waters, and saline waters. We will 
briefly consider each of these kinds. 

Sulphur Waters contain a considerable quantity 
of hydrogen sulphide, and this gas possesses such an 
unmistakable odor that no chemical skill is needed to 
determine its presence. The solid contents of such 
waters consist mostly of alkaline sulphides and sul- 
phates. Utah furnishes many remarkable examples of 
sulphur springs. The waters of the Warm Springs 
and of the Hot Springs at Salt Lake City are rare and 
wonderful mixtures. 

Carbonated Waters are such as contain an abun- 
dance of carbon dioxide gas, by virtue of which they 
dissolve large amounts of calcium carbonate and of 
other carbonates. Carbonated waters are of two kinds: 
those containing much lime in combination are known 
as calcium waters ; and waters containing iron com- 



MINERAL WATER. 237 

pounds as predominating ingredients are known as cha- 
lybeate waters. 

Calcium Waters. — it has been already shown that 
the solvent power of water for gases is increased by 
pressure, and we may conclude from this, that, within 
the crust of the earth, waters coming in contact with 
carbon dioxide would take into solution large propor- 
tions of the gas. This addition gives the water power 
to dissolve many mineral carbonates, of which lime- 
stone or calcium carbonate may be taken as a type. 
As such highly charged water reaches the surface as 
springs, the undue pressure being relieved, most of the 
carbon dioxide escapes, in consequence of which the 
lime carbonate falls from solution in the solid state. 
This may be deposited in such quantities as to form a 
curb of stone around the spring, and to incrust articles 
immersed in the water. Very remarkable carbonated 
springs exist at Soda Springs, Idaho, and at Midway, 
Utah. At the former place the waters are so highly 
charged with carbon dioxide that the escaping gas 
keeps the springs in constant and violent agitation. 
Any article placed in the water soon becomes coated 
with a deposit of lime carbonate. Such process is 
sometimes incorrectly spoken of as petrifaction ; it is 
simply an incrusting or covering, not a replacing by 
stone. A bunch of grapes or a bouquet of flowers 
may be completely covered in this way, and long after 
the soft fruit and the delicate petals have decayed , the 
stony casing remains, preserving the full form of the 
original. 

Chalybeate Waters contain iron in the form of 



238 DOMESTIC SCIENCE. 

ferrous carbonate. This substance is soluble in water 
containing free carbon dioxide, but not in pure water ; 
in this respect it resembles the lime carbonate already 
referred to. When the carbon dioxide escapes from 
such water, the iron carbonate is deposited from solu - 
tion ; under the influence of atmospheric oxygen, 
however, this soon changes to ferric oxide, and appears 
about the springs, and upon objects placed in the 
water, as a red or yellow incrustation. Typical illus- 
trations of this class of waters are found in Sevier 
Co., and in Millard Co., Utah. At the former place 
the deposits of ferric oxide are so pure and plentiful as 
to be used with very little preparation for making paints. 

Alum Waters are rich in iron and aluminum sul- 
phates, and frequently contain small quantities of free 
sulphuric acid. The strong styptic taste of alum is 
characteristic of such waters. Alum springs are not 
of common occurrence in the west. 

Siliceous Waters contain silica in solution, and 
are usually alkaline and always hot as they naturally 
occur in springs. Hot alkaline water appears to be 
the natural solvent of silica. Of this kind of thermal 
springs are geysers, the most noted of which occur in 
the Yellowstone Park of our own country ; others 
exist in Iceland and in New Zealand. As the water 
escapes from confinement, and as it cools, much of the 
silica is deposited from solution, thus forming the 
geyser craters.* 

*In some places the silica is deposited in a gelatinous condition 
to a depth of three or four inches. Trunks and branches of trees 
immersed in these waters are quickly petrified. Le Conte. 



MINERAL WATER. 239 

Saline Waters contain many earthy salts, among 
which the chlorides of sodium and calcium predom- 
inate. The celebrated Kissengen Springs in Germany 
belong to this class, as do also the famous Saratoga 
Springs in the United States. To this division of 
mineral waters belong also the waters of the ocean, 
and of salt and alkaline lakes. The composition of 
saline waters is very complicated ; indeed sea water 
contains all soluble compounds that are found in the 
earth, and that are capable of existing together in the 
same solution. The prevailing ingredient is sodium 
chloride. 

A very concentrated saline water is that of the Great 
Salt Lake, which contains on an average about 19 per 
cent, by weight of solid ingredients, or say 13,000 
grains per gallon of water. The author collected and 
analyzed a sample of Salt Lake water in December, 
1885, and found in it the following ingredients : 





Grams 


Per cent. 




per litre. 


by weight, 


Sodium chloride 


152.4983 


13.5856 


Sodium sulphate 


15.9540 


1.4213 


Magnesium chloride 


12.6776 


1.1295 


Calcium sulphate 


1.6679 


0.1477 


Potassium sulphate 


4.8503 


0.4321 



Total solid matter 187.6481 16.7162 

The proportion of solid matters in an inclosed 
body of water like the Great Salt Lake is variable 
according to the prevailing climatic conditions. Thus, 
during the dry and warm season, evaporation pro- 
ceeds much more rapidly than water is supplied by the 
inflowing streams, consequently at such times lake 



24 DOMESTIC SCIENCE. 

water becomes more concentrated. During the wet 
months, however, the supply far exceeds the loss by 
evaporation, and the water becomes correspondingly 
diluted. As a basis for comparison with the above 
figures, there are given below the results of an analysis 
of lake water collected in August, 1889 : 





Gva,\n< 


Ter cent. 




per litre. 


by 


weight. 


Sodium chloride 


182.131 




15.7430 


Sodium sulphate 


12.150 




1.0502 


Magnesium chloride 


23.270 




2.0114 


Calcium sulphate 


3.225 




.2788 


Potassium sulphate 


5.187 
226.263 




.4742 


Total solids 


19.5576 



In 1892 the lake water was even more concentrated. 
The average of four analyses of samples taken from 
the lake in September of that year showed the water 
as holding in solution 250.75 grams per litre, or over 
22 per cent, by weight. 

The water of the Dead Sea, in Palestine, is still 
more coiiceutrated. An analysis of a sample of Dead 
Sea water collected at a depth of 1,110 feet, by Capt. 
Lynch, showed the following composition : 

Per cent, by weight. 



Sodium chloride 


7.555 


Potassium chloride 


0.658 


Magnesium chloride 


14.889 


Calcium sulphate 


0.070 


Calcium chloride 


3.107 


Potassium bromide 


0.137 


Total solids 


26.416 



Temperature of Springs. — The average temper- 
ature of spring water is from 60° to 65° F., but min- 



MINERAL WATER. 241 

eral springs often far exceed this. Indeed some min- 
eral waters are discharged from the spring at a boiling 
temperature. The Hot Springs, near Salt Lake City, 
have a temperature of 128° F. The Monroe Springs, 
in Sevier Co., Utah, discharge water at 137.5° F., and 
certain hot springs, near Draper, Salt Lake Co., LTtah, 
emit water at a temperature of 158° F. The constancy 
of temperature in most of these springs is remarkable. 
Wells says : "There is evidence to show that the tem- 
perature of some hot springs has not diminished for 
upward of a thousand years.'' 

Medicinal Effects of Mineral Waters.— Before 

leaving the subject of mineral waters, reference should 
be made to the common belief that all such waters are 
of necessity valuable remedial agents in disease. In- 
deed, there seems to be a popular belief that any 
natural water possessing a particularly disagreeable 
taste or odor is surely good for the body. It is an 
undeniable fact that many mineral waters possess 
great therapeutic properties ; especially are they valua- 
ble for washing and bathing in cases of skin disease, 
gout, and rheumatism, and in rare cases it may be wise 
to administer the waters internally ; but there is a 
reckless carelessness now existing as to the use of 
such waters. They should be used in moderation and 
under skilled direction. Mineral water is to be re- 
garded as a medicine, not as a panacea ; and if admin- 
istered unwisely the water may prove positively harm- 
ful. 



24 2 DOMESTIC SCIENCE. 

REVIEW. 

1. What is mineral water ? 

2. Give a general classification of mineral waters. 

3. Give general characteristics of sulphur waters, with local 
illustrations. 

4. Give characteristics of carbonated waters, with illustra- 
tions. 

5. What sub -classes of carbonated waters are you acquainted 
with? 

6. What do you know of carbonated waters containing lime ? 

7. Of chalybeate waters ? 

8. State what you know of alum waters. 

9. Of saline waters, with some notable examples. 

10. What do you know of the average solid contents of the 
water of Great Salt Lake ? 

11. Name the principal mineral ingredients of the Salt Lake. 

12. Illustrate and explain the fluctuation in the proportions of 
dissolved solids to which the Salt Lake is subject. 

13. What do you know of the Dead Sea water ? 

14. State what you know of the temperature of spring waters. 

15. What is your opinion of the medicinal value of mineral 
waters ? 



COMPOSITION OF PURE WATER. 243 



CHAPTER 24. 

COMPOSITION OF PURE WATER. 

Chemical Elements and Compounds.— Know- 
ing now that natural waters are never pure, and having 
considered the process of distillation, by which chem- 
ically pure water may be prepared, it would be well to 
enquire concerning the nature and composition of this 
purest kind of water. From the earliest times of 
which we have general record till near the end of the 
eighteenth century, water was thought to be an ele- 
ment ; now it is known to be a compound. Elements 
are simple substances, such as man has never yet de- 
composed into other constituents; a compound, how- 
ever, is composed of at least two elementary sub- 
stances. As illustrations: gold, silver, iron, nitrogen, 
carbon, oxygen, sulphur, are elements; for not one of 
them has ever been decomposed by man. Thus far no 
chemist has been able to produce from pure gold any- 
thing but gold ; and so with each of the elements, of 
which now between 60 and 70 are known. On the 
other hand, common salt is an example of a compound ; 
it may be separated by chemical means into the two 
elements sodium and chlorine ; carbon dioxide is also 
a compound, it consists of carbon and oxygen. So, 
too, water is a compound, for it may be decomposed 
into the two ingredients, hydrogen and oxygen. 

Electrolysis of Water. — The decomposition of 



244 



DOMESTIC SCIENCE. 



water may be very beautifully and instructively illus- 
trated by passing a voltaic current through a quantity 
of water, and collecting the gases that result. If an ap- 
paratus similar to that shown in figure 86 be employed, 
the collecting tubes being filled with water and in- 
verted over the terminations of the conducting wires 




Fig. 86. 



Electrolysis of water. 

from the battery on the right, bubbles will be seen 
rising in the tubes as soon as the current is started. 
One tube is seen to fill as fast again as does the other. 
The double quantity of gas will be proved by investi- 
gation to be hydrogen, and the gas in the other tube 
to be oxygen. 

Decomposition of Water by Hot Iron.— If 

steam be passed through an iron tube containing scraps 
of iron heated to bright redness, the vapor will be 
decomposed, its oxygen combining with the metal in 



COMPOSITION OF PUKK WATER. 24 5 

the tube to produce an oxide of iron, and the hydro- 
gen escaping at the open end of the tube, where it may 
be collected. By this method also we prove that water 
consists of the elements hydrogen and oxygen. 

Oxyg'en. — The general mode of preparation and 
the principal properties of oxygea have been briefly 
considered in a preceding chapter (see pages 4 2 and 
43). It will be well at this stage to review the subject 
and re-read the pages referred to. 

HydPOg'en; its Ppeparation.— Hydrogen, how- 
ever, is to us a new element. To investigate its pro- 
perties we should prepare it in larger quantity than will 
be yielded by a weak battery current in water. The 
simplest and for our present purpose the best mode of 
preparing the gas is as follows : Arrange a generating 
bottle, with funnel, delivery tube, pneumatic trough, 
and collecting bottle. The apparatus shown in figure 
3, page 13, will answer our purpose well. Place 
within the bottle some scraps of zinc ; then adjust the 
cork and pour into the bottle through the funnel tube 
enough dilute sulphuric acid* or muriatic acid to cover 
the bits of zinc to the depth of an inch. Gas will 
soon collect in the inverted bottle ; discard the first 
bottleful ; it is mixed with air ; then collect several 
bottles of the gas. 



*Care must be exercised in diluting sulphuric acid, as great 
heat is developed in the process. The acid and the water should 
be measured separately — one volume of the former to three of the 
latter; the acid should then be poured in a small stream into the 
water, which in the meanwhile should be vigorously stirred. The 
mixing must be done in a vessel of glass or earthenware, as the 
acid will attack wood and metal. Eemember that suphuric acid 
is intensely corrosive and poisonous. 



246 



DOMESTIC SCIENCE. 



Properties of Hydrog'en. — By collecting and 

examining the hydrogen we shall find it to be a color- 
less gas, and if pure it will be devoid of odor, though 
the impurities of the materials used in its manufac- 
ture usually impart to the gas a disagreeable smell. 
It is also very light, exerting a buoyant effect on the 
vessels within which it is confined ; in fact, hydrogen 
is the lightest known substance. Its buoyancy may 

be prettily tested by filling 
with the dried gas a child's 
toy balloon; when re- 
leased this will rise swiftly 
through the atmosphere. 
Hydrogen is also in- 
flammable ; it may be 
burned at the mouth of 
the bottle, as shown in 
figures?. Another demon- 
stration of the combusti- 
ble nature of hydrogen 
may be made by passing 
the gas through a tube 
drawn at one end to a jet. 
The gas as it issues may 
be burned in a continuous 
flame. 

Synthesis and Analysis of Water.— While the 

hydrogen jet is burning, invert over it a cold dry bot- 
tle containing air or oxygen. A mist appears on the 
inside and drops of liquid may collect there. The 
combustion of hydrogen then marks a combination 




Fig. 87. 
Hydrogen burning. 



COMPOSITION OF PURE WATER. 24 7 

between this gas and the oxygen of the atmosphere, 
the result of the union is water. We have thus proved 
the composition of water by synthesis as well as by 
analysis. By analysis, or decomposition, we have sep- 
arated the water into its elements, hydrogen and oxy- 
gen ; this we accomplished by the aid of the voltaic 
current, and through the agency of heated iron. By 
synthesis, or union, we have combined the elements and 
produced the compound, water. 

It is remarkable that hydrogen, which burns with 
a very intense heat, and oxygen which is so vigorous 
a supporter of combustion, by their union should form 
a compound possessing the property of extinguishing 
fire. When oxygen and hydrogen are brought together 
in quantity, and a flame or an electric spark is applied 
to the mixture, a very violent explosion occurs, and 
water is produced by the union of the gases. 

The Oxy-hydrog'en Flame. — if a stream of oxy - 

gen be forcibly driven into the midst of a flame of 
burninghydrogen,the oxy-hydrogen flame is produced ; 
this is attended by the most intense heat known to be 
produced by chemical processes. In such a flame, 
steel wire will burn like wood in an ordinary fire ; zinc, 
copper, and all known metals may be deflagrated, 
many of them with characteristic flame tints ; even 
platinum, the most infusible of metals, may be readily 
melted by this means. Yet the flame is practically 
non-luminous; its great heat may be utilized, how- 
ever, in raising some incombustible solid to a state of 
incandescence. A piece of lime or of magnesia intro- 
duced into the flame is at once brought to a state of 



By volume. 


By weight. 


1 part 


8 parts 


2 parts 


1 part 



248 DOMESTIC SCIENCE. 

dazzling brilliancy. This is known as the calcium or 
Drummond light, and is of great service in the opera- 
tion of optical lanterns, and in other cases wherein a 
particularly brilliant illumination is desired. 

Constancy of Composition. — As a result of accu- 
rate experiments we know that pure water consists of : 

Oxygen 
Hydrogen 

These proportions are invariable, as indeed are the 
proportions of the constituent parts in any compound. 
In accordance with some great principle, which the 
mind of man has not fully comprehended, the elements 
of matter unite in fixed and unchangeable proportions. 
The discovery and proof of this fact is one of the greatest 
achievements of modern science. Not only is there 
order and system in the world of living things ; but even 
the dead minerals of earth, and the water of ocean and 
air, each is compounded according to unchanging 
law. 



REVIEW. 

1. Explain the difference between a chemical element and 
a compound. 

2. Show the difference between a compound and a mixture. 

3. Describe a demonstration of the compound nature of 
water. 

4. How may steam be decomposed ? 

5. Review the preparation and properties of oxygen (see 
chapter 3). 

6. Howwould you prepare hydrogen for experimental pur- 
poses ? 



COMPOSITION OF PURE WATER. 249 

7. State the chief physical properties of hydrogen. 

8. Describe demonstrations of some chemical property of 
hydrogen. 

9. Explain the chemical results of the combustion of hydro- 
gen in air. 

10. Define and illustrate " analysis" ; " synthesis." 

11. Explain the Drummond or calcium light. 

12. Describe the result of applying a flame to a mixture of 
oxygen and hydrogen. 

13. By what other means may union be effected in such a 
mixture ? 

14. State the composition of pure water. 

15. Show the constancy of composition of chemical com- 
pounds. 



PART III. 

FOOD AND ITS COOKERY. 



FOOD ITS NATURE AND USES. 253 



CHAPTER 25. 

FOOD ITS NATWRE AND USES. 

Bodily Need of Food. — Chemical analysis has 
demonstrated that the human body consists of at least 
fourteen separate and indispensable elements. These 
are nitrogen, carbon, oxygen, hydrogen, phosphorus, 
sulphur, sodium, potassium, calcium, magnesium, 
iron, silicon, chlorine, and flourine. Of these the 
first four are by far the most plentiful within the body. 
It is known that the organs of the living body are in 
ceaseless action, whereby great expenditure of force 
occurs, with consequent loss of material. It is there- 
fore necessary that the system be supplied with mate- 
rial from which to repair its various parts ; such supplies 
we called Food. 

What is Food ? — The term food may then be 
applied to substances that, when taken into the body, 
serve to nourish its tissues, and sustain its vital 
energy.* A perfect food would be one that contained 
all of the elements of the body in a digestible condi- 
tion, and in the proper proportion to supply the var- 
ious tissues of the body. Such a food -stuff is not 
known. Milk approaches this ideal standard, yet the 

♦"Foods may be defined as substances which, when taken into 
the alimentary canal, are absorbed from it and there serve either 
to supply material for the growth of the body, or for the replace- 
ment of matter which has been removed from it, eitlier after 
oxidation or without having been oxidized." Martin. 



254 



DOMESTIC SCIENCE. 



proportions in which the elements are present in milk 
fit it to be a complete food only for infants ; it is de- 
ficient in many of the substances required by adults. 
From these statements we will perceive at once the 
necessity of employing a mixed diet, in which we may 
supply with one article the elements lacking in an- 
other. 

Classification of Foods. — According to composi- 
tion, alimentary substances, or the simple constituents 
of foods may be classified as follows : 



.5^ 



f Water. 
Common Salt. 
And certain compounds of 
Lime. 
Iron. 
Sulphur. 
Phosphorus. 
Potassium. 
Silicon. 
Magnesium. 



(Potato Starch. 
Wheat Starch. 
Maize Starch, 
etc. 



Sugar. 



Saccharose. 
Glucose, 
etc. 



f Amyloids. ■( Gum 



O 01 

s-i m 



I Carbonaceous 
Substances. 

■{ Nitrogenous 
Substances 

or 
Proteids. 



|G, 



Vegetable Acids. 



TArabin. 
■{ Cerasin. 

I Vegetable Mucilage. 
I etc. 

fCitric Acid. 

Tartaric " 
{ Malic 

Oxalic 
[Pectin. 

■^ Fats and Oils. ( Volatile Oils. [Olein. 
L ^ Fixed Oils. /Palmitin. 

r Albumen. r^^^f/'^" 

^ Fibrin. "^ ^'^^• 

Gelatin. 
I Casein. 
L Gluten. 



00 a: 

C ^ 






Vinegar. 
Fruit Juices. 
Essential Oils. 

Spit-es- J Coffee. 

Artificial Drinks. jCocoa and Chocolate. 



FOOD ITS NATURE AND USES. 255 

Mixed Foods. — A well-regulated dietary should 
include a proper amount of each of these classes of 
food ; and by an instinctive tendency we select and 
combine foods, to accomplish this purpose. As an 
example, bread is rich in starch, a compound of the 
amyloid group; it contains a small proportion of glu- 
ten, which is a nitrogenous compound ; but it is very 
deficient in fat ; however, we are prone to add butter 
to our bread, thereby supplying the chief lack. But 
bread and butter is an incomplete food ; it is still poor 
in nitrogen, and we usually endeavor to add a nitro- 
genous element, such as meat or eggs, at our meals. 
Potatoes are rich in carbon and hydrogen, and in 
many of the mineral salts of food ; yet they are very 
deficient in nitrogenous substances, and we relish them 
best with meat. 

Moderation Needed in Animal Diet. — it is 

beyond doubt that many people indulge too freely in 
animal foods ; and others have adopted an intemper- 
ance of an opposite kind, by abstaining from animal 
matters entirely. Nitrogenous foods we must have, and 
these are advantageously supplied through the medium 
of animal products. It is not necessary that flesh be 
frequently eaten ; milk, butter, cheese, and eggs are 
rich in albuminoids. The indications of chemical and 
physiological science, and above these, the voice of 
reason and the experience of the human race, declare 
that though excessive indulgence in animal food is 
highly injurious, yet strict vegetarianism is not a 
proper course. 

The Quantity of Food needed for proper bodily 



256 DOMESTIC SCIENCE. 

support varies widely in different persons. The state 
of the person's health, the amount of exercise taken, 
the climate, and many other circumstances unite to 
regulate the demand for food. The natural appetite, 
unvitiated by improper habits, weakening depriva- 
tion, or unwarranted excesses, is one's best guide. 
From numerous observations, in many climes and on 
persons of different temperaments, it is believed that 
the aufra//e individual requirements call for 23 ounces 
dry solid matter, and 70 to 80 ounces of liquid per 
day. Dr. Hutchinson places the average daily quan- 
tity of food and drink for a healthy man at 6 pounds ; 
and divides this amount as follows : three and one-half 
pounds from the mineral kingdom, including water 
and salt; one and one-half pounds from the veg- 
etable kingdom, including bread, vegetables, and fruits ; 
and one pound from the animal kingdom, comprising 
meat, eggs, butter, and such. 

Digestibility of Food Stuffs. — Nof all substances 

containing the elements of the human body are fitted 
for use as food-stuffs. A food must contain the 
essential elements already named, in digestible condi- 
tio7i. As an example of this necessity, consider the 
case of carbon, which forms so large a proportion of 
most of our ordinary food materials, and is so indis- 
pensable to the well-being of the body. Carbon in 
its purest and uncombined state* is entirely indigesti- 

*The purest carbon exists in a crystalized form as the dia- 
mond. Other forms of unoombined carbon are graphite or 
plumbago (the "black lead" of pencils), charcoal, coke, gas- 
carbon, and lamp black. Though these consist almost entirely of 
this essential element of food, yet they are indigestible and con- 
sequently untitted for diet. 



POOD ITS NATURE AND USES. 257 

ble, and consequently valueless as food. A lump of 
charcoal contains far more carbon than does the same 
weight of bread ; yet the carbon of the bread may be 
assimilated within the body and become part of the 
tissues ; whereas charcoal, if introduced into the 
stomach, would serve mainly to derange the digestive 
functions. Another example, — nitrogen is abun- 
dantly present in the muscular tissues, and in 
some proportion it is present in all the bodily parts ; 
there is consequently a great demand for this element. 
The air about us contains nitrogen to the extent of 
four-fifths of its entire bulk ; yet this atmospheric 
nitrogen is valueless as a food ; it enters the body at 
every respiratory inhalation, and escapes unchanged 
when the breath is expelled. Free nitrogen is not 
assimilated by the tissues; indeed the body seems un- 
able to use the chemical elements as food, until they 
have been brought together as compounds through the 
agency of plant or animal life. 

Plants Supply Food. — This is true of all human 
and animal bodies ; they cannot live on unorganized 
matter ; plants may absorb and assimilate mineral sub- 
stances, but animals do not possess this power. In 
our own bodies we can use comparatively complicated 
materials only, — substances that have been already 
organized under the influences of life. It is a natural 
law that men and animals shall be supported by the 
plant kingdom ;* if they feed upon animal bodies, 
these have been nourished by plants, so that their sub- 

* " Plants may be considered as the laboratory in which Nature 
prepares aliment for animals." Richerand, 



258 DOMESTIC SCIENCE. 

sistence comes directly or indirectly from the vegetable 
kingdom. 

Food-Stuffs Must be Readily Soluble. — Now we 

may very properly ask, what are the essentials of this 
condition of digestibility in food materials? In the 
first place, to be available as food, substances must be 
readily soluble in the digestive fluids. This dissolv- 
ing action may be in some degree imitated outside the 
body. Chemical mixtures have been prepared, analog- 
ous in composition to the digestive juices ; and in 
these, food materials have been dissolved. Thus one 
part of the digestive process may be carried on in 
glass flasks before our eyes. Any soluble substance 
may be thus dissolved ; the artificially prepared mix- 
ture acts alike on all soluble matters. Not so, how- 
ever, with the body ; its digestible apparatus is more 
complicated than a mere collection of vessels and 
tubes ; it is a sensitive, living organism*, and rejects 
food that is not pleasing to the senses. 

Foods Must be Palatable.— A food preparation 
that excites disgust in the mind* will be digested only 
with difliculty, and in some cases not at all ; though it 
may be from a chemical point of view very nutritious. 
Several years ago Edwards and Balzac, two French 
academicians, performed some noted experiments by 
feeding dogs on prepared food and carefully noting 
results. The animals were kept for days on a prepara- 



* The digestive organs, as indeed is the case with all other 
bodily parts, are readily affected by the varying conditions of the 
mind. Many a person while eating with relish, has suddenly 
"lost his appetite" under the influence of some strong emotion, 
either joyous or distressing. 



MINERAL INGREDIENTS OF FOOD. 259 

tion of gelatine soup mixed with bread, — chemically 
speaking a very nutritious diet, though almost devoid of 
flavor. After a few meals of this stuff, the dogs evinced 
decided dislike, and finally refused to eat more of the 
insipid mess though they were suffering the pangs of 
starvation. The experimenters then mixed with the 
daily allowance of gelatine about two tablespoonfuls of 
meat - broth ; this gave to the soup a pleasing flavor ; 
the dogs ate ravenously of it. One animal that had 
already lost a fifth of its weight under the pure gelatine 
regimen, began immediately to improve, and in 
twenty -three days from the time of the change in diet 
the creature was heavier than before the experiments 
were begun. Tests of a similar kind have been com- 
menced on human beings. Men have been kept on 
pure chemical preparations, containing all the needed 
elements, but devoid of attractive savors ; and it is 
beyond doubt that, had the trials been sufficiently pro- 
longed, fatal results would have followed. 

Purpose of Cookery. — Much of our food has 
to be prepared for the table by a process of cook- 
ing. The aim of this art is to render food 
materials more easily digestible than they are in the 
raw and purely natural state, and to develop pleasing 
savors.* Any operation in cookery which fails to 
accomplish both of these ends, serves its purpose in- 

* In their efforts to teach people that mastication and insaliva- 
tion of food are important steps in the digestive process, physi- 
ologists have long declared that "digestion begins in the 
mouth;" now, however, this saying has with propriety been 
changed, and may be more properly rendered as "digestion should 
begin in the cook room." 



260 DOMESTIC SCIENCE. 

completely. In its effects upon human kind the art of 
cookery exceeds the influence of the fine arts. The 
use of poorly cooked and insipid food has led many 
people to indulgence in spirituous liquors, whereby 
they hoped to stop the unsatisfied craving for a pleasing 
diet. 



REVIEW. 

1. Define food. 

2. What would be the characteristics of a perfect and com- 
plete food ? 

3. Write a classification of foods. 

4. Show the necessity of a variety of food materials. 

5. What is your opinion as to the propriety of using meat 
for food ? 

6. Show the necessity of the food materials we eat being in a 
soluble condition. 

7. Into what physical condition must all food stuffs be re- 
duced before they can be absorbed and assimilated within the 
body? 

8. Why should food be made pleasing to the senses ? 

9. Describe the notable experiments of the French scientists^ 
Edwards and Balzac. 

10. What is the object of cooking ? 

11. What bad effects may follow the effect of poorly cooked 
and unsavory food ? 



MINEKAL INGKKDIENTS OF FOOD. 261 



CHAPTER 26. 

MINERAL INGREDIENTS OF FOOD. 

Mineral Substances in the Body.— Certain 

mineral matters are indespensable to the growth of the 
body ; the chief of these are water, common salt, and 
certain compounds of calcium, magnesium, iron, sod- 
ium, and potassium ; also chlorine which is present in 
common salt ; and sulphur, phosphorus, and silicon 
which are combined with the metals named above. 
Except water and salt, however, these mineral sub- 
stances are absorbed within the body only when in 
combination with organic matters. 

The phosphates of calcium, magnesium, and potas- 
sium are needed for the formation of bone, muscle, 
brain and nervous tissue ; iron is an essential ingred- 
ient of the red corpuscles of the blood ; the alkalies, 
potash and soda, are required for the blood and for 
many of the solid tissues ; salt is needed throughout 
the system, and water composes from two -thirds to 
three- fourths of the whole bodily weight. The im- 
portance of the mineral ingredients of food is therefore 
clear. 

Water has already received a somewhat extensive 
treatment, an entire section of this little book having 
been devoted to its consideration. A mere mention at 
this point must therefore suflSce. The table on page 
179 shows the proportions of the liquid present in 



262 DOMESTIC SCIENCE. 

different tissues of the body. Water is a universal 
carrier. No solid matter is absorbed in the bodies of 
men, animals, or plants except in solution. 

Common Salt exists as an essential constituent of 
all solids and fluids of the human body. In the blood, 
salt is present in greater quantity than any other mineral 
ingredient, except water. Dalton gives the following 
proportions of salt present in certain tissues and prod- 
ucts of the human body ; the figures state the parts of 
the solid present in a thousand parts of the substances 
named : 





Common salt present 




in 


1000 parts. 


Muscle 


- 


2. 


parts 


Bone 


- 


2.5 


" 


Cartilage 


- 


2.8 


<< 


Milk 


- 


1. 


<< 


Saliva 


- 


1.5 


" 


Bile 


- 


3.5 


" 


Blood 


- 


4.5 


" 


Mucus 


• _ 


fi. 


(( 



Salt is present as a natural constituent in many 
articles of diet ; but to supply the requisite quantity 
it is added to the food as a condiment. Moderation 
in its use, however, is essential to health. It is pos- 
sible to acquire a disordered appetite through the 
lavish use of salt ; the craving for condiments once 
started within the body is liable to grow till it becomes 
a serious habit. Salt excites the nerves of taste, and 
renders pleasing food that otherwise would be insipid 
and tasteless. In the absence of salt, food could be 
but imperfectly digested, and a long continued depri- 
vation of this substance would seriously affect the 
bodily powers, and would lay the system open to the 



MINERAL INGREDIENTS OF FOOD. 263 

inroads of disease. In Holland there was once a law, 
that for certain grave offenses, prisoners should be fed 
on food entirely free from salt ; this was regarded as 
the severest punishment that could be inflicted. Few 
sufferers long survived treatment of this kind ; their 
craving for salt grew so intense as to induce insanity ; 
and their bodies became fatally disordered. Salt is no 
less essential to animals than to the human being. 
Without salt our domestic animals become dull and 
diseased; their skins grow rough, and much of the 
hair falls. Stock -keepers know from experience the 
value of providing their animals with a free supply of 
salt. Wild beasts whose wariness secures them 
against being entrapped by tempting baits of food, 
are readily captured at natural or artificially prepared 
"salt licks." In some parts of the world, where salt is 
scarce, the article commands a very high price.* 



*"In man, the desire for salt is so great tliat in regions wliere it 
is scarce it is used as money. In some parts of Africa a small 
quantity of salt will buy a slave, and to say that a man commonly 
uses salt at his meals is equivalent to stating that he is a luxurious 
millionaire. In British India, where the poorer natives regard 
so few things as necessaries of life that it is hard to levy any 
excise tax, a large part of the revenue is derived from a salt tax, 
salt being something which even the poorest will buy. As regards 
Europe, it has been found that youths in the Austrian Empire 
who have fled to the mountains, and there led a wild life to 
avoid the hated military conscription, will, after a time, though 
able abundantly to supply themselves with other food by hunt- 
ing, come down to the villages to purchase salt, at the risk o 
liberty, and even of life."— Dr. Newell Martin. 

"Animals will travel long distances to obtain salt. Men will 
barter gold for it; indeed among the Gallas and on the coast of 
Sierra Leone, brothers will sell their sisters, husbands their wives, 
and parents their children for salt. In the district of Accra, on 
the gold coast of Africa, a handful of salt is the most valuable 



264 DOMESTIC SCIENCE. 

Natural Occuprences ot Salt. — Yet the natural 

sources of salt are apparently inexhaustible. Vast 
deposits of it occur in the earth, and streams of water 
flowing to the sea carry the substance in solution to 
their ocean bed. Sea water contains on an average 
three per cent, of salt ; the waters of the Great Salt 
Lake contain about eighteen per cent, of their weight 
of salt. Some varieties of commercial salt are very 
impure, containing considerable quantities of magne- 
sium and lime in combination. Utah possesses 
natural salt in apparently unlimited quantities ; vast 
deposits of rock salt occur throughout Sanpete and 
Sevier Counties, and so in other parts ; and the waters 
of Salt Lake could supply the world with salt for a 
long period. 



thing on earth after gold, and will purchase a slave or two. 
Mungo Park tells us that with the Mandingoes and Bambaras the 
use of salt is such a luxury that to say of a man ' he flavors his 
food with salt,' is to imply that he is rich; and children will suck 
apiece of rock salt as if it were sugar. No stronger mark of 
respect or affection can be shown in Muscovy than the sending of 
salt from the tables of the rich to their poorer friends. In the 
book of Leviticus it is expressly commanded as one of the ordin- 
ances of Moses, that every oblation of meat upon the altar shall 
be seasoned with salt, without lacking, and hence it is called the 
Salt of the Covenant of God. The Greeks and Romans also used 
salt in their sacrificial cakes; and it is still used in the services of 
the Latin church — the ^ parva mica,^ or pinch of salt, being, in the 
ceremony of baptism, put into the child's mouth, while the priest 
says, ' Receive the salt of wisdom, and may it be a propitiation to 
thee for eternal life.' Everywhere, and almost always, indeed, it 
has been regarded as emblematical of wisdom, wit, and immor- 
tality. To taste a man's salt was to be bound by the rites of 
hospitality; and no oath was more solemn than that which was 
feworn upon bread and salt. To sprinkle the meat with salt was to 
drive away the devil, and to this day, nothing is more unlucky 
than to spill the salt."— Letherby. 



MINERAL INGKtDlENTS OF FOOD. '265 

Lime is the most abundant of the solid inorganic 
ingredients of the human body. It is present in all 
tissues and liquids of the system though in widely 
varying quantities. It occurs mostly as calcium phos- 
phate, and less abundantly as calcium carbonate. 
According to Dalton, the following figures show the 
quantity of calcium phosphate in 1000 parts of the 
tissues and fluids named : 





Lime phosphate 




in 1000 parts. 


Teeth 


650 


Bones 


550 


Cartilages - 


40 


Muscles 


2.5 


Blood 


0.3 


Gastric juice 


0.4 



The hardest substance of the body is the enamel of the 
teeth ; this consists mostly of lime salts, the phosphate 
being in excess. Lime imparts strength and rigidity 
to the bony skeleton ; a deficiency of it causes pliancy 
and disease of the bones. In early life, the bones are 
naturally soft, because, ossification being then incom- 
plete, the animal matters of the bones exceed in 
quantity the mineral substances; children, therefore, 
require a comparatively large amount of lime salts ; 
and this is best supplied through means of a generous 
diet of milk and grain preparations, with a very mod- 
erate allowance of animal food other than milk. 

A common and an instructive demonstration of the 
importance of lime compounds in the bones, may be 
made by soaking a bone in dilute acid, thereby remov- 
ing the mineral substances. Procure a rib for the 

9 



266 DOMESTIC SCIENCE. 

purpose : it being in shape long and slender will be 
well adapted. Place the bone in a mixture of one part 
muriatic acid and fifteen parts water; allow it to re- 
main in the acid during a few days, then remove and 
wash it. The bone will be found soft and pliable, so 
that it may be easily bent in any desired form, or even 
tied in a knot as illustrated in figure 88. The animal 
tissue that remains after the treatment with acid will 
dry and become hard and transparent. 




Fig. 
Bone, after treatment with acid, tied in a knot. 

Iron constitutes about one -thousandth part of the 
weight of the blood ; it is essential to the red color of 
the blood corpuscles. In the entire body there is about 
five drachms of iron. When the blood is deficient in 
this element, it becomes pale in color, the skin as- 
sumes an unnatural pallor, and the bodily strength 
very rapidly diminishes. It is then a common practice 
in medicine to administer iron in a soluble form, usu- 
ally as the tincture of iron per-chloride, or as iron 
citrate. Iron is supplied in the food through the 
medium of milk and eggs, and many vegetable articles 
of diet. 



MINERAL INGREDIENTS OF FOOD. 267 

Sulphur and Phosphorus, though present in very 
small quantities, are still essential within the body. 
These substances occur mostly in combination, as 
phosphates and sulphates of calcium, magnesium, 
potassium, and sodium. Dr. Foster says: "The ele- 
ment phosphorus seems no less important from a bio- 
logical point of view than carbon or nitrogen. It is as 
absolutely essential for the growth of a lowly being 
like penicillium* as for man himself. We find it 
peculiarly associated with the proteids, apparently in 
the form of phosphates, but we cannot explain its 
role. The element sulphur, again, is only second to 
phosphorus, and we find it as a constituent of nearly 
all proteids, but we cannot tell exactly what would 
happen to the economy if all the sulphur of the food 
were withdrawn.'' 

The compounds of magnesium, potassium, sodium, 
and silicon, which are called for in much smaller 
quantity than are the substances already named, are 
present in ordinary food stuffs, and are seldom found 
in insufficient quantity within the body. 

Mineral Ing'redients of Food Within the 

Body. — The mineral elements of food as a rule do not 
undergo chemical change by decomposition or combi- 
nation within the body. They are absorbed with the 
food and enter the tissues, forming an indispensable 
part of the body substance ; then they are removed by 
the processes of secretion, and their place supplied by 

*Pe7i*ctZWMw— the common green mold or mildew, so common in 
damp situations, as upon old shoes, bread, vegetables, fruits, and 
jams. It is a living thing; a plant belonging the order of fungi. 



268 DOMESTIC SCIENCE. 

other particles of the same kind. The changes pro- 
duced upon mineral matters by the processes of cook- 
ing are so light as to be inconsiderable for our present 
purpose. 



REVIEW. 

1. Name the principal mineral matters indispensable to the 
bodily growth. 

2. Show the occurrence of mineral matters in the different 
parts of the body. 

3. Show that water is an essential ingredient of living bodies. 

4. Show the occurrence of salt within the human body. 

5. Give instances of the ill effects of depriving the body of 
salt. 

6. Relate some of the instances quoted to illustrate man's 
craving for salt. 

7. What do you know of the natural occurrence of salt in 
Utah? 

8. Show the occurrence of lime within the human body. 

9. Describe a demonstration of the value of lime as an in- 
gredient of the bones. 

10. What do you know of the occurrence of iron in the body ? 

11. Discuss the value of the compounds of sulphur within the 
body. 

12. Of phosphorus compounds. 

13. Of magnesium compounds. 

14. Of potassium compounds. 

15. Of sodium compounds. 

16. Of silicon compounds. 



ORGANIC INGREDIENTS OF FOOD. 269 



CHAPTER 27. 

ORGANIC INGREDIENTS OF FOOD ; CARBl>NACEOUS FOODS : 
STARCH, SUGAR, GUM. 

Organic Food Matters. ^Certain food materials 
occur in Nature as products of animal or vegetable life 
only ; such are called organic foods, to distinguish 
them from mineral matters. The organic ingredients 
of food may be classified as shown on page 254. 

Carbonaceous Food Substances; Amyloids; — 

These claim our attention first ; they are so named 
because of the predominance of carbon as an element 
of their composition. The amyloids, such as the 
starches and the sugars, consist entirely of carbon, 
hydrogen, and oxygen ; they are therefore known 
chemically as carbohydrates. The fats contain the 
same elements, though in different proportions, 
oxygen being present in them in very small quantity. 
The amyloid group of food substances includes starch, 
sugar, and gum, of each of which there are many 
varieties. 

Starch in its prepared form appears as a white 
powder, possessing a gritty feel if rubbed between 
the fingers. When viewed through the microscope 
the powder will be seen to consist of minute rounded 
grains, the exact form varying in starches from differ- 
ent sources. Figure 89 represents starch granules 



270 



DOMESTIC SCIENCE. 




from the potato ; these particles are somewhat like 
clam shells, the surface of each being marked by wav- 
ing lines concentric about a point known as the hilum, 

which point marks the 
place at which the 
grain was originally 
attached to the cell 
wall. Grains of pota- 
to starch vary in size 
from Vioooo to Ysoo of 
an inch in diameter. 
The grains of wheat 
starch are represented 
Fig. 89. in figure 90 ; these are 

Potato starch granules; (magnified) g^jj^ller than the pre- 
ceding ; they rarely exceed Vtoo inch in diameter, and 
from that they vary to ^/loooo- Starch granules from 

wheat present a circular 
outline ; though many of 
the grains are flattened, 
so that in a side view 
they present a narrow 
edge. Starch from oats 
consists of large, com- 
pound granules, which 
under pressure may be 
readily broken into sec- 
tions. Starch grains 
from maize, or Indian 
corn, and the grains of rice starch are irregular in 
form, many of them presenting an angular outline. 




Fig. 90. 
Wheat starch; (magnified) 



ORGANIC INGREDIENTS OP FOOD. 



271 



Starch in Plants. — Starch is of common oc- 
currence in plants. At certain seasons the substance 
accumulates within the body of the plant in great 
quantity ; starch is the form in which the plant 
stores its food material for future growth.* Its wide 
occurrence is shown by the following table : 







Average percentage 


of starch. 


Potatoes .... 15.70 


Peas 






32.45 


White beans . 






33.00 


Kidney beans 
Buckwheat 






35.94 
52.00 


Rye flour 






56.00 


Oatmeal 






59.00 


Wheat kernel 






59.5 


Rye meal 






61.07 


Barley meal . 






67.18 


Wheat flour . 






• 72.00 


Maize 






80.92 


Rice 






85.07 



Certain articles of diet consist almost entirely of 
starch, such are corn -starch, arrowroot, sago, tapioca 
and rice ; these will receive our future attention. For 
the present let us examine the living plant and inform 
ourselves of the way in which starch is stored within 
it. The microscope has revealed the important fact that 
all plant tissue consists of thin-walled inclosures 
known as cells, and within these the secretions peculiar 
to the plant are formed. Figure 91 shows three sec- 



*The food material being stored within the plant in the form of 
starch, and starch being insoluble in cold water, the plant stores 
are safe from loss by rains or floods. This insoluble starch is 
changed to a soluble sugar as fast as the plant requires the 
material for its own growth. 



272 



DOMESTIC SCIENCE. 



tions of plant tissue containing starch granules ; the 
upper left hand sketch illustrates a potato cell ; the 
other upper section is that of an oat seed, and the 
lower one represents a wheat kernel. 




Fig. 91. 
Plant cells filled with starch. 



Starch is- scarcely soluble at all in cold water; but, 
when heated in water near the boiling point, the 
grains absorb liquid, and burst, forming a jelly or 
paste. In this form, starch is of use for laundry pur- 
poses; this " boiled starch" is not a true solution, 
however ; the starch and water may be almost entirely 
separated by freezing. The fact that cold water has 
so little solvent effect on starch, suggests a method for 
its preparation. 

Grate some potatoes to the condition of a fine pulp ; 
place this within a bag of coarse muslin ; immerse in 
water and knead well under the liquid. The water 



ORGANIC INGREDIENTS OF FOOD. 273 

soon becomes milky, and after a time a white powder 
settles to the bottom. This is starch ; it may be re- 
moved from the water and dried. Wheat flour may 
be treated in the same way and starch procured from 
it. 

Sug'ar is a sweet vegetable product, found in the 
juice of cane, the roots of beets, the sap of certain 
trees, and in many fruits. In a chemical sense there 
are many kinds of sugar, the chief of which are sac- 
charose or cane sugar, glucose or grape sugar, levulose 
or the sugar of fruit, and lactose or sugar of milk. 

Saccharose is found in a fairly pure form, as loaf 
and granulated sugar of commerce, though a still 
purer kind is met with in the uncolored and crystal- 
lized rock -candy. This is the most sweetening of all 
common sugars. It is prepared chiefly from the sugar 
cane, sugar beet, and sugar maple. It may also be 
produced from sorghum, and in smaller quantity from 
the juices of many other plants, as maize, parsnips, 
carrots, etc. The following table shows the propor- 
tions of sugar present in different products : 

Per cent. 

of sugar. 

Indian corn - - - 1.5 

Peas - - - - 2. 

Ryemeal - - - 3,2 

Oatmeal - - 4.8 

Barley meal - - - 5.2 

Wheat flour - - - 5.4 

Beets - - - - 9.0 

Ripe pears - - - 11.5 

Ripe peaches - - 16.5 

Ripe cherries - - 18.1 

Figs • - - - 62. 



274 DOMESTIC SCIENCE. 

Saccharose melts at about 356° F., and if cooled 
rapidly from that temperature it forms a granular mass 
known as barley sugar ; of this the prepared candies 
largely consist. If a higher heat be applied to sugar it 
becomes burnt or caramelized. Caramel is used as a 
coloring agent in cooking. 

The Ppeparation of Saccharose from vegetable 

liquids is an instructive process. The juice is obtained 
by pressure ; it is then mixed with a quantity of lime 
to neutralize any free acid present and to assist in set- 
tling the impurities ; the clarified juice is then evapor- 
ated, and the product is crude, brown sugar, com- 
monly known as Muscovado sugar. This is to be 
purified. It is dissolved in water and the solution is 
decolorized by being heated with bone black or animal 
charcoal. It is then clarified by an addition of albu- 
men, usually in the form of blood ; this by its coagula- 
tion and settling carries most of the impurities to the 
bottom. The liquid is then evaporated, and the crys- 
talizing sugar is separated by centrifugal power. To 
prevent burning of the sugar, the evaporation is con- 
ducted in vacuum pans, which are vessels so con- 
structed as to cause the removal of the vapor as fast as 
formed ; by these means the pressure upon the liquid 
is reduced and the boiling proceeds at a much lower 
temperature. The purified article appears as loaf or 
granulated sugar. 

The syrup remaining after the crystallization, is 
known as molasses, sometimes called treacle, though 
much molasses is made from sorghum juices without 
any separation of sugar. The difliculties thus far ex- 



ORGANIC INGREDIENTS OF FOOD. 275 

perienced in the preparation of sugar from sorghum 
have been largely due to the ready inversion of the 
contained saccharose, by which it becomes changed 
into glucose and levulose. These obstacles have been 
mostly overcome during recent years, and a very 
good article of sugar is now obtainable from sorghum 
cane. . 

Glucose or grape sugar occurs in many fruits, being 
specially plentiful in grapes. This sugar does not 
readily crystallize, and its sweetening power is not 
more than three-fifths that of cane sugar. It may be 
prepared from starch by simple processes. Several 
large establishments in the United States are devoted 
entirely to the manufacture of glucose from Indian 
corn. As a result of extended tests it is believed that 
glucose is no more unwholesome as an article of food 
than is true cane sugar, though doubtlessly extensive 
frauds are in operation by which saccharose is largely 
adulterated with the cheaper glucose. The transform- 
ation of starch into glucose takes place in the sprout- 
ing of seeds ; plants store their food supplies within 
the seeds as insoluble starch ; when germination begins 
the starch becomes glucose, and is easily absorbed and 
assimilated by the growing plant. It is an easy matter 
also by chemical means to transform saccharose into a 
mixture of glucose and levulose ; but thus far no sat- 
isfactory method of making the reverse transformation, 
namely, from glucose to the sweeter saccharose, has 
been devised. 

Veg'etable Gums are by no means inconsiderable 
as elements of food, though in this country they are 



276 DOMESTIC SCIENCE. 

seldom used in special food preparations. The princi- 
pal gums that enter into the composition of food stuffs 
are arabin or gum arabic, cerasin or the gum from 
cherries and plums, and vegetable mucilage which 
occurs in almost all. kinds of plants. Gum is present 
in considerable quantity in grains and in preparations 
from them. The following table, according to Von 
Bibra, shows the proportion of gum in several dry 
plant products : 





• Per cent, of 




gum. 


Wheat kernel 


4.50 


Wheat flour 


6.25 


Wheat bran 


8.25 


Rye kernel 


4.10 


Rye flour 


7.25 


Rye bran 


10.40 


Barley flour 


6.33 


Barley bran 


6.88 


Oatmeal 


3.50 


Rice flour 


2.00 


Millet flour 


10.60 


Maize meal 


3.05 


Buckwheat flour 


2.85 



Dextrin. — By heating starch to a temperature of 
300° F. it undergoes a remarkable change, assuming a 
yellow color and becoming readily soluble in water. 
This substance is a kind of gum, and has been named 
dextrin. It is largely used as a dilutent for other 
gums, and in a prepared state as a mucilage is sold as 
British gum, Alsace gum, and starch gum. It has 
strong adhesive properties. 



ORGANIC INGREDIENTS OF FOOD. 277 

REVIEW. 

1. What is an organic food ? 

2. Give a general classification of organic foods. 

3. What are the distinguishing characteristics of carbona- 
ceous food substances ? 

4. Name the chief members of the amyloid group of food 
substances. 

5. Describe the microscopic appearance of potato starch. 

6. Of starch from other plants. 

7. Show the abundance of starch in certain plants. 

8. Describe the occurrence of starch within the plant cells. 

9. What do you know of the action of cold and hot water on 
starch ? 

10. How would you prepare starch from potatoes ? 

11. Name the principal sugars, giving the chief sources of 
each. 

12. Show the occurrence of sugar in plants. 

13. What do you know of saccharose ? 

14. Of glucose ? 

15. Of levulose? 

16. Describe briefly the processes of sugar refining. 

17. What do you know of vegetable gums as food articles ? 

18. Show the occurrence of gum in plants. 

19. What do you know of dextrin, its preparation, properties, 
and uses ? 



278 DOMESTIC SCIENCE. 



CHAPTER 28. 

CARBONACEOUS INGREDIENTS OF FOOD, CONTINUED. 
VEGETABLE ACIDS AND FATS. 

In composition, the Vegetable AcidS are closely 
allied to the sugars and starches already considered. 
The name vegetable acids expresses at once the nature 
and occurrence of the substances ; they give sourness 
to fruits and many vegetable products, though they 
are present in plants in very small proportion only. 
In food they serve to impart a pleasant, pungent taste, 
and vrithin the body, they undergo ultimate digestion 
as do the starches and the sugars.* The chief of the 
vegetable acids are citric acid, tartaric acid, malic acid, 
and oxalic acid. 

Citric Acid is the sour principle of lemons ; it 
occurs also in oranges, citrons, cranberries, and unripe 

♦The following appears (quoted) in the "Scientific American," 
Aug. 20th, 1892. "We know that many vegetable and fruit pro- 
ducts are esteemed rather for their pleasant or refreshing taste 
and for their anti -scorbutic properties, than for any nutritive 
value which they may be assumed to possess. Yet even fruits of 
that character are especially valuable as additions to our daily 
diet, on account of the potash salts and mild vegetable acids they 
contribute to the blood. * * * Many persons know from exper- 
ience how much more pleasant and agreeable fruit is when gath- 
ered and eaten direct from the tree. This is undoubtedly in part 
due to the freshness and briskness of the vegetable acids con- 
tained in the fruit, which when so gathered and eaten have not 
time to change into any other siibstance. Stale fruit, on the other 
hand, is unpalatable from the very fact that it has lost this pun- 
gent and brisk taste." 



VEGETABLE ACIDS AND FATS. 279 

tomatoes ; associated with other acids it is found in 
strawberries, raspberries, currants, gooseberries, and 
cherries ; and in smaller quantity, combined with lime 
as calcium citrate, it is found in artichokes, onions, and 
beets. Citric acid is an ingredient of many common 
sour and effervescent beverages. 

Tartaric Acid is the prevailing acid of grapes ; it 
is found, too, in many other fruits ; and in the com- 
bined state as tartrates of potassium and calcium, it is 
also found in potatoes, pine apples, cucumbers, and 
in sumach berries. The chief source of the acid is 
argol or crude potassium tartrate, which collects as 
sediment in vats of fermenting grape juice. Purified 
potassium tartrate is known as cream of tartar. In a 
pure state tartaric acid crystallizes in clear large plates ; 
it is intensely sour to the taste, and is used in pre- 
paring effervescing drinks. For such purposes, how- 
ever, it is but an inferior substitute for citric acid. 

Malic Acid is the chief cause of sourness in 
apples, pears, small fruits, plums, peaches, and cher- 
ries. It is widely distributed throughout the vegeta- 
ble kingdom, especially in immature fruits. In com- 
bination with potassium it is abundant in the juices of 
rhubarb. The acid is seldom prepared in a pure state, 
as but little practical use has been found for it ; it rnay 
however be purified as a white crystalline solid very 
readily soluble in water, the solution possessing an 
intensely sour taste. 

Oxalic Acid exists in sorrel, rhubarb, and many 
other plants. It is usually found in combination with 
calcium and potassium as oxalates of those metals. 



280 DOMESTIC SCIENCE. 

Potassium oxalate has long been sold as "salts of 
sorrel," and has found domestic application as a means 
of removing ink stains and iron -mold spots from 
clothes. Purified oxalic acid appears as transparent 
crystals ; it is intensely poisonous, and many fatalities 
have resulted from its use. It has many times been 
mistaken for Epsom salts, which indeed it greatly re- 
sembles in outward appearance. 

Pectin OF Veg'etable Jelly is very closely akin to 
the vegetable acids just considered. This is largely 
prepared from fruits by heating them with water, 
sweetening and straining. The solution becomes a 
jelly in cooling. The acids present in jelly so pre- 
pared are known as pectic and pectosic acids. 
These by long continued heating become trans- 
formed into metapectic acid which is so readily 
soluble that a solution containing it no longer solidifies 
on cooling. This is well known to housewives who 
have tried to concentrate a fruit jelly by long contin- 
ued heating; usually a syrupy liquid only is obtained. 
It is a general belief that sugar is essential to the pro- 
duction of a jelly from vegetable juices ; the sugar, 
beside its sweetening effect, absorbs the excess of 
water present, and leaves the pectic and pectosic acids 
free to soldify by cooling. 

Acetic Acid is of vegetable origin, though not oc- 
curring free in Nature ; it is the sour substance in 
vinegar. This will receive brief attention in the 
chapter on "Auxiliary foods." 

Veg'etable Acids Tpansformable into Amy- 
loids. — It has already been stated that the vegetable 



VEGETABLE ACIDS AND FATS. 281 

acids are allied in chemical nature to the amyloids 
already described. Examples of the transformation of 
acids into starch and sugar are common in Nature. 
Thus, in the green state, apples are intensely sour; as 
the ripening process proceeds, however, the sourness 
is less marked, and a chemical examination shows an 
increase in sugar, and a corresponding diminution of 
malic acid and starch. 

Fats and Oils constitute the next group of car- 
bonaceous food elements. These substances consist of 
carbon, hydrogen, and oxygen, the last named element 
however, being present in very small proportion only. 
The fats are therefore spoken of as hydro -carbons. 
Some fats both of animal and of vegetable origin, are 
characterized by containing a small amount of phos- 
phorus ; these are known as phosphorized fats. The 
oil from peas contains 1.17 per cent, phosphorus; 
bean oil .72 per cent. ; vetch oil .5 per cent. ; barley 
oil .28 ; rye oil .31 ; oat oil .44.* 

Relation between Fats and Oils.— There ap- 
pears no essential difference of composition between 
the solid fats, and the liquid oils, the consistency 
depending greatly upon the temperature. Tallow 
may be reduced by warming to a mobile liquid ; and 
olive oil may be solidified by cold. In Africa, the 
fat of the palm tree is in the state of liquid palm-oil ; 
with us the same substance is semi -solid and is known 
as palm -butter. 

Oils, Fixed and Essential.— Of common oils 



♦These figures are give^ on the strength of Toepler's experi- 
ments. 



282 



DOMESTIC SCIENCE, 



there are two main groups, the fixed oils, and the 
volatile or essential oils. The former are the more 
important as food elements ; they may be recognized 
by their power of producing permanent grease stains 
when placed upon paper ; even gentle warming fails 
to remove such spots. A volatile oil if smeared on 
paper, produces but temporary stains : these entirely 
disappear by heating. Some volatile oils do slight 
service as auxilliary foods ; but for the present we 
confine ourselves to a consideration of fixed oils and 
fats only as they constitute our main source of this 
class of foods. 

Veg'etable Fats are largely obtained from seeds ; 
good examples are furnished by the oily seeds of flax, 
colza, cotton, peanut, butternut, and sunflower. The 
following speciflcation shows the amount of oil present 
in certain vegetable products : 











Per cent, of oil 


Meadow grass .... 0.8 


Meadow hay 








3.0 


Clover hay- 








3.2 


Wheat bran 








1.5 


Wheat kernel 








1.6 


Wheat flour 








1.5 


Maize kernel 








8.0 


Pea 








3.0 


Rice 










0.8 


Buckwheat 










0.4 


Olives 










32.0 


Cotton seed 










34.0 


Flax seed 










34.0 


Colza seed 










45.0 


Cocoanuts 










47.0 


Filberts 










60.0 



There is a strong prejudice, none the better because 
popular, against the use of vegetable oils in food. 



VEGETABLE ACIDS AND FATS. 283 

As a rule we prefer the poorest of lard, to the purest 
oils of olive and palm ; yet as cooking media the plant 
oils are in all respects superior. Cotton -seed oil has 
been proved to be nutritious and wholesome ; it has 
lately found extensive use in the preserving of fish, 
and cotton planters now find the seed of their crop 
almost as valuable as the fibre. True, the price of 
refined vegetable oil is at present high when compared 
with the cost of animal fats ; the crude oil, however, 
is far cheaper than the unrefined animal product, and 
as soon as a demand arises for pure vegetable oils, 
there will be no lack of supply at a cheap rate. 

Animal Fats. — Fat is also present in common 
articles of animal food, as these figures will show : 

Per cent of fat. 

Cows' milk - • - 3.13 

Goats' " - - - - 3.32 

Ordinary meat - - - 14.03 

Liver of ox - - - 3.89 

Tolk of eggs - - - 28.75 

Common Fats. — The principal common fats are 
enumerated and briefly described below : 

Olein is abundant in ordinary oils ; being the most 
fluid of common fats, it may be prepared in quantity 
from oils and the softer fats. 

Palmitin is plentiful in African palm oil ; it occurs 
also in beeswax and tallow. It is fluid only during 
warm weather, or under the influence of artificial 
heat. 

Stearine may be prepared from tallow. It is pres- 



284 DOMESTIC SCIENCE. 

eut in all common fats, and being solid at ordinary 
temperatures imparts solidity to other fats. 

Some PPOpertieS of Fats. — Fatty substances are 
generally insoluble in water ; yet under certain condi- 
tions, oils may be suspended in water in a very finely 
divided state; such a mixture is known as an emul- 
sion. A little oil shaken up in water to which a 
minute quantity of soda had been added, will exem- 
plify an emulsion. The microscope shows in such a 
mixture the oil drops still separate and perfect. Milk 
is an example of a natural emulsion. A farther char- 
acteristic of all fats is their property of forming soaps 
with the alkalies. 

Fats constitute a very important part of food mate- 
rial. AVhen eaten, fatty matters deyelop great bodily 
warmth, they are therefore well adapted as a diet for 
cold climes. Under the influence of severe cold, a 
strong, natural craving for fat is developed. Seamen, 
wintering In Arctic regions, eat fats with relish. The 
Esquimaux in their wintry home devour immense 
quantities of oleaginous matter.* 



*Dr. Hutchinson says, "The Esquimau consumes daily from 
ten to fifteen pounds of meat or blubber, a large proportion of 
which is fat. The Laplander will drink train oil, and regards tal- 
low candles as a great luxury." 

The need of fat in the food of children is very great. Dr. 
Edward Smith says on this subject, "Children who dislike fat 
cause much anxiety to parents, for they are almost always thin, 
and if not diseased, are not healthy. If care be not taken they 
fall into a scrofulous condition, in which diseased joints, enlarged 
glands, sore eyes, and even consumption occur; and every effort 
should be made to overcome this dislike. If attention be given to 
this matter of diet, there need be no anxiety about the possibility 
of increasing the quantity of food consumed; whilst by neglect, 



VEGETABLE ACIDS AND FATS. 285 

REVIEW. 

1. Name the principal vegetable acids occurring in food stuffs. 

2. State what you know of citric acid. 

3. Of tartaric acid. 

4. Of malic acid. 

5. Of oxalic acid, 

6. Describe the occurrence and properties of pectin. 

7. Why is it that a fruit jelly by continued heating becomes 
permanently liquid? 

8. What is the general composition of fats ? 

9. With what classes of oils are you acquainted ? 

10. How may we distinguish between fixed oils and volatile 
oils ? 

11. Show the occurrence of fats and oils in plants. 

12. Name some of the principal vegetable oils. 

13. What do you know of olein, palmitin, stearin ? 

14. What is an emulsion ? 

15. Show the value of fats as food. 

the dislike will probably increase until disease is ^educed. The 
chief period of growth, viz. — from seven to sixteen years of age — 
is the most important in this respect, for a store of fat in the body 
is then essential. Those who are inclined to be fat, usually like 
fat in food, and then it maybe desirable to limit its use. Some 
who cannot eat it when hot like it when cold, and all should select 
that kind which they prefer." 



286 DOMESTIC SCIENCE. 



CHAPTER 29. 

NITROGENOUS INGREDIENTS OF FOOD. 

Nitrogenous Food Necessary. — Nitrogen is an 

essential constituent of most tissues of the human 
body ; there is need, therefore, of nitrogenous food to 
nourish the parts. The importance of foods of this 
nature is so great that they have been called flesh 
formers. We must not be led by this appellation to 
the extreme belief that no food material devoid of 
nitrogen is of value ; starches and sugars, gums and 
fats, are of indispensable service in sustaining bodily 
heat, and they serve also as sources of actual energy, 
which manifests itself as muscular force. It is a plain 
fact nevertheless, that non- nitrogenous matter can but 
imperfectly build up tissues of which nitrogen forms 
an important constituent. 

From the general resemblance of all nitrogenous 
food compounds to albumen, the first and commonest 
of the group, they are often called albuminoids, some- 
times also proteids : this last name is derived from the 
Greek and signifies "first" or "most important," 
having reference here to the imperative need of nitro- 
genous substances within the body. The albuminoids 
are composed of nitrogen, carbon, hydrogen and oxy- 
gen ; many of them contain also a small proportion 
of sulphur. 

Albumen may properly be studied as the first of 



NITROGENOUS INGREDIENTS OF FOOD. 287 

the group ; it is found in an almost pure condition, 
except for an admixture with water, in the white of 
egg. The word ''albumen" is of Latin derivation, 
from albus, meaning white, and is so applied because 
of the white color assumed by the substance when 
heated. A careful study of the properties of albumen 
is essential to an understanding of many operations in 
cooking. Procure a fresh egg, separate the yolk from 
the white, and place the latter in a glass test tube, in- 
sert a thermometer, and immerse the lower part of the 
tube in water which is being gradually heated. As 
the temperature within the tube ranges from 130° to 
140° F., white, opaque fibers appear in the substance; 
these increase till the whole mass of albumen has been 
converted into a white, semi-solid coagulum. This 
change will be complete when the temperature has 
risen to 170° F., and any greater heat will harden the 
egg substance, and if long continued will convert it 
into a tough, apparently indigestible mass. It is plain 
then that a temperature of 170° F. is sufficient to 
properly coagulate the albumen. 

In the liquid condition, albumen is soluble in water ; 
after coagulation, however, it is almost entirely insol- 
uble. As an illustration of this, the white of egg may 
be shaken or stirred in cold water, and completely 
dissolved therein ; on heating the liquid to the proper 
temperature the albumen will appear in the solid form 
as flakes. Albumen as a food is mainly derived 
from the animal kingdom, though the substance 
exists in the juices of plants, and in many seeds and 
grains. 



288 DOMESTIC SCIENCE. 

Fibrin, another albuminoid, is present in consider- 
able quantity in many animal fluids. The clotting of 
blood is due to the spontaneous coagulation of the 
contained fibrin. To procure fibrin for examination, 
place a quantity of fresh blood in an open vessel, agi- 
tate or whip the liquid with a wisp of fine twigs or 
wires ; the fibrin will gather upon the bundle in the 




Fig. 92. 
Fibers of lean meat. 

form of stringy, semi- liquid masses. Blood so defib- 
rinated has lost its power of clotting.* The separated 

* Exposure to the air induces the clotting of blood. This change 
is caused by the hardening of the fibrin— a constituent of the 
plasma— by which the blood corpuscles are entangled so as to 
form a plug or clot. A yellowish liquid separates as the clot 
forms; this is known as blood-serum. The benefits resulting 
from this property of blood can scarcely be over-estimated. In 
the case of a severed vein or artery, the fiow is checked by clot- 
ting, while the healing of the vessel is in progress. Did this 
property not exist in the blood, bleeding could be stopped only 
by artificial means. Among birds the clotting of blood is espec- 
ially rapid. This feature is a great benefit to these winged crea- 
tures, for the great muscular exertion of flying would cau«e pro- 
fuse bleediiig from very small wounds, were it not for the stop- 
ping of the injured vessels by the blood clots. In this we see 
divine provision even for the accidents to which animals and men 
are subject. 



NITROGENOUS INGREDIENTS OF FOOD. 289 

fibrin may be washed and purified ; then it appears of 
a yellowish color, and is soluble in hot water. 

Take now a bit of raw lean meat, thoroughly wash 
it in water ; the liquid becomes colored from the red 
juices taken from the meat, and that which remains is 
of a purplish tint and of a fibrous structure. These 
fibers consist mainly of animal fibrin, though the dis- 
tinguishing name of myosin has been applied to such. 
Figure 92 is a sketch of the magnified fibers of lean 
meat. 

Fibrin is also present in certain plants, especially in 
juices. If turnip juice be exposed to the air, after a 
short time it deposits solid flakes of coagulated fibrin. 
For purposes of distinction this has been named vege- 
table fibrin. 

Gelatin is a very important member of the albu- 
minoid family of foods. It is present in most of the 
tissues of the animal body, including bones and carti- 
lage. In a purified form gelatin is insoluble in cold 
water, though it dissolves readily in hot water, and 
the solution on cooling assumes the condition of a 
jelly. Gelatin is the chief ingredient of all animal 
jellies. One x>unce of pure gelatin is capable of com- 
bining with one and a half pounds of water to form 
jelly. The purest commercial form of gelatin is isin- 
glass, which is a preparation from the swimming blad- 
ders of fishes. Specimens of gelatin from different 
sources possess widely varying degrees of solubility. 
Calves' foot jelly is a delicious food ; jelly made from 
the feet of cows is less prized because of its inferior 
solubility. The turtle's body is rich in gelatin, and 



290 DOMESTIC SCIENCE. 

as a consequence it is in great favor as a prime ingre- 
dient of soup ; a somewhat inferior and much less 
expensive luxury is mock turtle soup, which contains 
gelatin from pigs' feet, calves' heads, and the like. 

The material of which the edible birds'' nests are 
composed is a kind of gelatin. These nests are con- 
structed by a species of swift* inhabiting the coasts of 
China, Sumatra, and Java. The birds produce large 
quantities of slimy saliva, which, on drying, becomes 
solid and transparent gelatin ; it is readily soluble in 
hot water, the solution constituting the much-prized 
jelly. 

The Value of Gelatin as Food has been made the 
subject of special inquiry by certain members of the 
French Academy, as already stated (page 258). M. 
Edwards, one of the experimenters, draws the follow- 
ing conclusions from his observations and tests. t 

"1. That gelatin alone is insufficient for alimenta- 
tion. 2. That although insufficient, it is not un- 
wholesome. 3. That 2:elatin contributes to alimenta- 



*This variety of swift, the "esculent swallow" as it is commonly 
called, delights to build in caves; and it is stated that a single 
cavern in Java, to which the birds have taken a decided liking 
as a place of abode, brings its proprietor an income of $25,000 a 
year rental, the sole value of the place depending upon the nests 
therein constructed. This cave the swifts share good naturedly 
with the bats, the latter holding possession during the day, and 
the birds occupying the lodgings at night. In shape the nests 
resemble hanging bags or pouches, and they are held firmly 
against the wall through the adhesive properties of the salivary 
mucus. Birds' nest soup ranks among the costliest of table deli- 
cacies of its class; the clean, dry nests sell in the market for their 
own weight in silver. 

tThe English construction is the translation of Mr. Mattieu 
Williams. 



NITROGENOUS INGREDIENTS OF FOOD. 291 

tion, and is suflScient to sustain it when it is mixed 
with a due proportion of other products which would 
themselves prove insufficient if given alone. 4. That 
gelatin extracted from bones, being identical with that 
extracted from other parts, and bones being richer in 
gelatin than other tissues, and able to afford two- 
thirds of their weight of it, there is an incontestible 
advantage in making them serve for nutrition in the 
form of soup, jellies, paste, etc. ; always, however, 
taking care to provide a proper admixture of the other 
principles in which the gelatin soup is defective. 
5. That to render gelatin soup equal in nutritive and 
digestible qualities to that prepared from meat alone, 
it is sufficient to mix one-fourth of meat soup with 
three-fourths of gelatin soup; and that, in fact, no 
difference is perceptible between soup thus prepared 
and that made solely from meat." We are then to 
regard gelatin as a very efficient food when properly 
flavored by admixture with other substances ; alone it 
is repulsive to the system. Gelatin is furnished by the 
animal kingdom only. 

Casein is the chief albuminoid of milk, in which it 
exists to the extent of from three to six per cent., and 
constitutes the greater part of the curd of milk. In 
fresh milk the casein is held in solution ; by coagula- 
tion, however, as in cheese making, the substance is 
rendered almost entirely insoluble in water. The co- 
agulation of casein in milk may be effected by adding 
a small quantity of acid ; though the change is best 
brought about by the addition of rennet, which is an 
infusion of the mucous lining of a calf's stomach. 



292 DOMESTIC SCIENCE. 

Unlike albumen, casein is not coagulable by heat. A 
common example of casein solidifying in the presence 
of an acid is seen in the spontaneous souring of milk ; 
under particular circumstances the sugar in the milk 
is decomposed, lactic acid being formed in the process ; 
this acid causes a speedy precipitation of the casein as 
a voluminous curd. When milk is curdled through 
the addition of rennet, the casein carries with it from 
solution many of the mineral salts, notably the phos- 
phates, which were originally present in the milk ; pre- 
cipitation by acid, however, removes these substances 
from the curd, and they are lost in the whey. Cheese 
formed by the first method therefore is superior to that 
made by the addition of acid. 

When separated from the other ingredients of milk 
and purified, casein appears as a yellowish, translucent 
solid, not unlike horn ; in water this is ordinarily in- 
soluble, but in weak alkaline solutions it readily dis- 
solves. These facts will be of service to us in our 
subsequent examination of cheese as food. 

Casein is found in small quantities in certain vege- 
tables, especially in the leguminosse — a family of plants 
including peas and beans. If such seeds be finely 
ground and then treated with water, the casein passes 
into solution, and may be precipitated as a coagulum 
by the addition of acid. Dried peas and beans will 
yield 20 per cent, of their weight of vegetable casein. 
The Chinese manufacture from peas a good article of 
vegetable cheese, which is almost indistinguishable by 
chemical means from milk cheese. 

Gluten is a tough, elastic substance,! present in 



NITROGENOUS INGREDIENTS OF FOOD. 



293 



flour, and imparting to dough its property of sticki- 
ness. It may be prepared by kneading flour with 
water on a fine sieve, after the manner indicated by 
figure 93. The liquid soon becomes milky from the 
starch granules washed from the dough; the gluey 
mass remaining is a mixture of substances, containing 
considerable quantities of vegetable fibrin and of veg- 
etable casein, and about 20 per cent, of pure gluten. 
In a dried state, gluten is a horn-like, semi-trans- 
parent solid, insoluble in 
cold water ; slowly and but 
feebly soluble in hot wat- 
er ; readily soluble in acetic 
acid (strong vinegar) and 
in dilute alkalies. 

Properties of the Al- 
buminoids. — Before leav- 
ing the albuminoids it will 
^. „^ be well to consider some 

Fig. 93. 

Separating the gluten of flour, characteristics of the group. 
As already stated, they all contain a considerable 
quantity of nitrogen. Then further, they all possess 
the peculiar property of coagulation, though under 
different conditions; thus, heat coagulates albumen, 
acid or rennet is needed to curdle casein ; blood fibrin 
coagulates spontaneously. All albuminoids are readily 
decomposable by heat, with evolution of an odor like 
that of burning horn. Under influences of moisture 
and warmth, albuminoids undergo a destructive 
change, known as putrefaction, in which process the 
albuminoid matter becomes partially liquified, and 




294 DOMESTIC SCIENCE. 

gives off certain gases of disgusting odor. Albumi- 
nous matters have the power of acting as chemical 
ferments, so that if a small quantity of such in a de- 
composing state be placed with fresh material of the 
same kind, putrefactive changes are speedily excited 
throughout the whole mass. A bit of sour gluten in- 
troduced to dough soon "leavens the whole." 



REVIEW. 

1 . What are albuminoids or proteids ? 

2. Define "albumen." 

3. From what source would you procure albumen for study ? 

4. Explain the effect of heat on albumen. 

5. What do you know of the temperature at which albumen 
coagulates and hardens ? 

6. State what you know of fibrin. 

7. How would you obtain fibrin for study ? 

8. Explain the clotting of blood, 

9. Show the great advantages to human and animal life re- 
sulting from the clotting of blood. 

10. What is gelatin ? 

11. What do you know about edible birds' nests ? 

12. What is your opinion of the value of casein as an article 
of food ? 

13. Why is gelatine alone poorly adapted for food ? 

14. What is the prominent albuminoid in milk ? 

15. How may casein be separated from the other ingredients 
of milk ? 

16. Explain the souring of milk. 

17. Why does milk curdle as it becomes sour ? 

18. What is rennet? 

19. Why is cheese made by the use of rennet superior to cheese 
make by the use of acid? 

20. What do you know of vegetable casein? 

21. Describe the principal properties of gluten. 

22. How would you prepare gluten for study? 

23. State the principal characteristics of the albuminoid group 
of foods. 



VEGETABLE FOODS AND THEIR COOKERY. 295 



CHAPTER 30. 

VEGETABLE FOODS AND THEIR COOKERY. 

Having considered the chief ingredients of ordinary 
foods, it will be profitable now to devote some 
attention to the food stuffs that supply these sub- 
stances. All of our common food materials are mix- 
tures of several of the alimentary substances already 
referred to; it is common, therefore, to speak of 
ordinary foods as " compound aliments." Let us first 
consider the chief foods derived from the vegetable 
kingdom. 

1, TUBERS, BULBS, AND ROOTS. 

Potatoes cannot properly be classed as roots ; they 
have buds, (eyes), and rudimentary leaves (the little 
scales behind the buds), which no true roots possess ; 
they are to be regarded as enlarged underground 
stems, to which the common name tubers has been ap- 
plied. Potatoes are very extensively used as articles of 
food, though in chemical composition they are deficient 
in nutritive matters. On the average, potatoes contain 
from 76 to 80 per cent, of water ; and of the remain- 
ing 20 or 24 per cent, dried matter, but a very small 
proportion is nitrogenous. In this respect the potato 
is even inferior to rice, which has long been regarded 
as one of the least nitrogenous of ordinary foods. Prof. 
Johnston's analysis show the following relative com- 



296 DOMESTIC SCIENCE. 

position of potatoes and rice, only the dried sub- 
stances being considered in either case : 





Potato 


Rice 




per cen . 


per cent, 


Gluten 


5 


9 


Starch, sugar and gum 


81 


89 


Fat - 


1 


0.5 


Mineral salts 


4 


0.5 



According to Smith, 2.5 pounds of potatoes are 
required to furnish the amount of carbon ordinarily 
contained in one pound of bread ; and 3.3 pounds of 
potatoes contain no more nitrogen than is contained in 
a pound of bread. AVilliams states that a pound of 
oatmeal is worth 6 pounds of potatoes, as regards the 
contained nitrogenous matter.* A potato diet is at 
best a very poor one, and a person subjected to it has 
to devour immense quantities of the vegetable to 
obtain the nutriment requisite for the support of the 
body. However, potatoes serve an admirable purpose 



* "My own observations in Ireland have convinced me of the 
wisdom of William Corbett's denunciation of the potato as a 
staple article of food. The bulk that has to be eaten, and is 
eaten, in order to sustain life, converts the potato eater into a 
mere assimilating machine duriug a large part of the day, and 
renders him unfit for any kind of mental or bodily exertion. 

The effect of potato feeding may be studied by watching the 

work of a potato -fed Irish mower or reaper, who comes across to 
work upon an English farm where the harvesters are fed in the 
farm house, and the supply of beer is not excessive. The im- 
provement of his working power after two or three weeks of 
English feeding is comparable to that of a horse when fed upon 
corn, beans and hay, after feeding for a year on grass only. My 
strictures on the potato do not apply to them as used in England, 
where the prevailing vice of our ordinary diet is that it is too 
carnivorous. The potatoes we eat with our meat serve to dilute 
it, and supply the farinaceous element in which flesh is defi- 
cient."— W. Mattied Williams. 



VEGETABLE POODS AND THEIR COOKERY. 29 7 

in diluting the fare of persons who are prone to ex- 
cess in the use of over- stimulating and extra-nourish- 
ing food. The mineral substance or ash of potato 
tubers is very rich in potash, and contains a consider- 
able proportion of other mineral compounds so 
essential in foods ; but much of this valuable material 
is removed by the ordinary methods of cooking. 

Cooking" of Potatoes. — The practice of peeling 
potatoes, and then immersing them in water, results 
in the washing away of many of their mineral salts. 
A potato contains within itself sufficient water for its 
perfect cookery ; and here we must pause long enough 
to inform ourselves of the chief differences between 
raw and cooked potatoes. Figure 91 upper left hand 
sketch, represents an enlarged view of a thin slice of 
potato tuber, showing the cells with their contents of 
starch granules ; and figure 89 shows the starch 
particles separated and more highly magnified. 

It will be remembered as a property of starch that 
the substance is insoluble in cold water; but that 

it may be made to absorb a 
considerable amount of hot 
water. In cooking a potato, 
its starch granules absorb water 
and burst; a single grain pre- 
senting some such an appearance 
Fig. 94. as is shown in figure 94. As a 

BurstiBg starch granule, j-^gyit of heating prepared starch 
in water, a gelatinous mixture is produced ; this 
condition is prevented in the case of the potato ; be- 
cause the starch grains within the tuber are protected 

10 




'2 98 DOMESTIC SCIENCE. 

by stout cell walls, and the albumen of the potato 
coagulates through the heating proce.«s and thus still 
further protects the starch. The starch of mature 
potatoes, when heated, absorbs nearly all their con- 
tained water, and thus the tubers become dry and 
mealy: young potatoes, when heated, and indeed all 
kinds if cooked in a superabundance of water, be- 
come waxy, because a considerable amount of water 
remains unabsorbed. From the standpoint of economy 
and wholesomeness, the best methods of cooking pota- 
toes are roasting and steaming ; by either process the 
contained juices are raised to the cooking temperature, 
and are absorbed by the swelling starch particles. If 
" boiled "* at all, the least injurious way is to cook 
them with their skins still in place, leaving the peeling 
for a subsequent operation. In some parts of Ireland, 
the people depend largely upon potatoes for their sup- 
port, and among them, experience has taught the 
ruinous waste of peeling potatoes before cooking. 

Onions are thickened parts of the stems of plant, 
and are botanically called bulbs. The onion is rich in 
nitrogenous matter, and is correspondingly nutritious. 
Its strong odor is due to the presence of a peculiar 

* It is a common but still a grossly improper practice to speak 
of things that have been kept for a time in boiling water, as being 
boiled. Only liquids can boil, and in boiling they are converted 
into vapor; thus water boils to steam ; alcohol in boiling produces 
alcohol vapor; iron may be boiled, but it must first be melted to 
the liquid state, then, if sufficiently heated, the molten metal may 
be converted into vapor of iron. Potatoes cooked in water are 
not boiled, any more than is the iron of the cooking vessel 
boiled. The water boils, however, and the effect of the boiling 
temperature is to produce within the potato the desired changes 
of cookery. 



VEGETABLE FOODS AND THEIR COOKERY. 299 

sulphurized oil, commonly known as garlic oil. In 
Spain and Portugal, onions are used as staple articles 
of diet. As a result of chemical analysis, Johnston 
states that the onion contains from 25 to 30 per cent, 
of gluten.* Onions possess valuable medicinal prop- 
erties, and the moderate use of the bulbs, either cooked 
or raw, is generally beneficial. On most people the 
physiological effect of onions is of a soothing kind, 
and in many instances the effects are decidedly sopor- 
ific. 
Turnips, Carrots, Parsnips, and Beets are true 

roots. They are rich accumulations of plant nutri- 
ment, being indeed the treasure vaults in which the 
growing plants have stored their gathered wealth, for 
use during the second year of their growth. These 
plants are biennials ; during the first season they do 
not blossom at all ; their energies are devoted to the 
absorption and storage of food material, which if the 
growth be uninterrupted, will be used by the plant 
during the next year's stages of flowering and seed 
bearing. Man avails himself of their labors by culti- 
vating the plants till they have accumulated their 
wealth of food, which then he appropriates to his own 
use. 



* "It ranks," says he, " in this respect with the nutritious pea 
and the gram of the East. It is not merely as a relish, therefore, 
that the wayfaring Spaniard eats his onion with his humble crust 
of bread, as he sits by the refreshing spring; it is because exper- 
ience has long proved, that, like the cheese of the English 
laborer, it helps to sustain his strength also, and adds — beyond 
what its bulk would suggest, to the amount of nourishment which 
his simple meal supplies." 



300 DOMESTIC SCIENCE. 

All the roots named possess less dry substance than 
do potatoes, weight for weight; it will be remembered 
that potatoes contain on an average of 20 to 25 per 
cent, solid matter, while according to the figures of 
Dr. Youmans, turnips contain about 10.5 per cent, 
solid matter ; yellow turnips 13.5 per cent., mangel 
wurtzel 15.5 per cent., carrots 14.22 per cent., beets 
10.9 per cent., and parsnips 19.6 per cent. The 
nature of the solid contents, however, is such as to 
place the roots far above the potato as tissue-forming 
food. The nitrogenous ingredients of the dried mangel 
wurtzel amount to nearly twice as much as do those 
of the dried potato. Radishes are true roots; they 
are used mostly as salad, and as such are eaten raw. 
Their nutritive value is low. 

In cooking, roots undergo changes analogous- to 
those already described in the case of potatoes ; — the 
contained starch granules absorb water, swell and 
burst ; the albumen coagulates and the lignin or 
woody fibre, which is present in all vegetable tissues, 
becomes softened. If cooked in water, much of the 
mineral matter will be removed ; steaming and roast- 
ing are far better processes. The skin should be un- 
disturbed until after cooking. 

2. LEAVES AND LEAF STEMS. 

These are less extensively used as articles of human 
food than are most other parts of plants. The nutri- 
tive qualities of leaves are shown by their composition, 
and by the fact that herbivorous animals, including 



VEGETABLE FOODS AND THEIR COOKEKY. 301 

even those of gigantic bulk, derive their chief support 
from leaves. 

Cabbag^e and Other Greens. — Cabbage is among 

the commonest of leaf foods used by man. The 
plant contains 90 per cent, water ; the remaining 10 
per cent, of solids is rich in nitrogenous matter, and 
contains a small proportion of sulphurized compounds. 
Cabbage, therefore, supplies the ingredients in which 
potatoes are deficient, and the union of the two vege- 
tables is a good one, and with the addition of a little 
fat, makes a mixture that is generally nutritive. 

Spinach, dandelion leaves, nettle tops, turnip leaves, 
and the fleshy stems of asparagus are often used as 
''greens." They are all nutritive and valuable foods. 

Salads.— Lettuce, water cress, garden cress, young 
mustard plants and celery, furnish leaves and leaf -stalks 
for food, and such are largely used in the raw state as 
salads. Lettuce contains a milky juice which is pos- 
sessed of narcotic properties. From the juice of the 
native plant lactucarium is prepared ; this is used in 
medicine as a substitute for opium. The use of salads 
as food is productive of good from the fact that raw 
plants, when eaten, supply the body with an abun- 
dance of mineral salts ; these ingredients are frequently 
lacking in cooked vegetables. The Welsh peasant, 
and the Swiss mountaineer would be unable to preserve 
health on their ordinary diet of cheese and bread, but 
for the addition of raw salads in abundance. In this 
connection it should be known that there are many 
valuable sources of food growing wild about our 
houses ; but these we are apt to call weeds, and to treat 



302 DOMESTIC SCIENCE. 

them with disdain. Comparing customs of different 
peoples we find a very wide range of salad plants in 
constant use.* 

3. FRUITS. 

Fruits are common articles of food. Most of them 
are of a pulpy consistency, and contain a large pro- 
portion of water, with varying amounts of sugar, 
vegetable acids and pectin or vegetable jelly ; there are 
also present peculiar aromatic substances which give 
to fruits their characteristic flavors. We know com- 
paratively little of the exact composition of fruits. 
Experience has proved them to be pleasing and whole- 
some, and in moderate amounts they may profitably 
be introduced in any ordinary dietary. Fruits may be 
eaten raw or in a preserved form ; most kinds may 
also be dried and kept without decomposition for long 
periods. Dried fruits should be cooked in water; in 
the process they will absorb large quantities of the 
liquid, and become once more pulpy and juiceful. 

* M. Vitmorin, President of the Botanical Society of France, in a 
lecture on "Salads," (Mar.h, 1890), stated that the French people 
excel in the use of salad preparations. He laid stress upon the 
nutritive value of salads as sources of potash and other mineral 
salts, which are commonly eliminated in the process of cooking. 
Among the various plants that are used as salads in France, he 
enumerated the leaves of lettuce, corn-salad, common chickory, 
water-cress, dandelions, (used green, blanched and half blanched), 
capucin, endives, purslane, (used in small quantities only), salsify 
tops, (described as being of a pleasant nutty flavor), witloof or 
Brussels chickory, roots of celcriac, rampion and radish; the 
bulbs of stachys, the stalks of celery, the flowers of nasturtium, 
and yucca, the fruit of capsicum and tomato, and, in the south of 
France, rocket, picridium and Spanish onions. Various herbs are 
added to a French salad as flavors or garnishes, such as chervil, 
parsley, olives, shallot, and borage flowers. 



VEGETABLE FOODS AND THEIR COOKERY. 303 

General Composition of Fruits. — The follow- 
ing table, compiled by Berard* shows the average 
chemical composition of five unripe and eight ripe 
fruits, comprising apples, pears, gooseberries, grapes, 
plums, cherries, apricots, and peaches : 







Unripe. 


Ripe, 


Water 




85.7 


78.7 


Albuminoids ' - 




0.7 


O.fj 


Sugar 




4.0 


12.9 


Vegetable acids - 


- 


1.5 


1.3 


Pectose and gum 




4.3 


3.7 


Cellulose, etc. 


- 


3.8 


2.8 


4. 


SEEDS. 







Seeds represent in nutritive value the richest of 
ordinary plant products, being indeed the accumula- 
tions of food material which the plants have stored for 
their offspring. Leguminous seeds, or those that grow 
in pods, such as peas and beans, are among the most 
concentrated of vegetable foods. Analyses by Horsford 
and Krocker, show table peas to consist of : 







Per cent, 


Albumen 


and Casein 


28.02 


Starch 


- 


38.81 


Gum 


- 


28.50 


Skin 


- 


7.65 


Ash 


. 


3.18 



The nitrogenous element of peas and beans is mostly 
vegetable casein, which has already been spoken of as 
the basis of Chinese vegetable cheese. 



* Quoted in " Scientific American," Aug. 20, 1892. 



304 DOMESTIC SCIENCE. 

REVIEW. 

1. Why are potatoes not to be considered as true roots ? 

2. What do you know of the mineral ingredients of potatoes ? 

3. Show the abundance of starch in potatoes. 

4. Explain the principal changes which a potato undergoes 
in cooking. 

5. Define "boiling." 

6. Show that potatoes alone form a very inferior food. 

7. Define "tuber," " bulb," "root." 

8. State what you know of onions as food. 

9. Of turnips, carrots, parsnips, and beets. 

10. Name the principal leaves used as food. 

11. What do you know of cabbage as a food ? 

12. Wherein lies the value of raw salads, used moderately ? 

13. Name the principal salad materials in common use. 

14. What do you know of fruits as food ? 

15. Of seeds? 



GRAINS AND BREAD. 305 



CHAPTER 31. 

VEGETABLE FOODS CONTINUED GRAINS AND BREAD. 

Among the most important of vegetable seeds used 
as food for man are the grains ; and of these, wheat, 
barley, rye, oats, buckwheat, and rice are the kinds 
most commonly employed. 

Wheat is the staple food stuff; its chief prepara- 
tion, bread, has long been known as the "staff of 
life." The average composition of wheat may be rep- 
resented as follows : 



AVater 


11 to 15 


per 


cent 


Gluten 


12 to 18 






Starch 


53 to 64 






Sugar 


7 to 8 






Gum 


5 to 6 






Bran 


1 to 3 






Ash 


2 to 3 







These figures are the results of numerous analyses 
of specimens from many different sources. When a 
thin section of a wheat grain, properly mounted, is 
examined under the microscope, a very regular ar- 
rangement of its constituent parts is revealed. Figure 
95 represents a portion of such a section ; A shows 
the coats of the seed ; B marks a row of cells which 
are rich in gluten ; O shows the interior cells con- 
taining starch granules. 

The ash of wheat is particularly rich in phosphoric 
acid, and other mineral ingredients of great service 
within the body. 



306 



DOMESTIC SCIENCE. 



The first process by which wheat is prepared for use 
as human food is one of crushing or grinding ; this 
is usually performed between stones or rollers. The 
resulting powder is then sifted and bolted, for the pur- 
pose of separating the coarse and fine particles. The 
outer layers of the grain, in the figure marked A and 
B, constitute the bran ; this, as separated in milling, 
amounts to about 15 per cent, of the gross weight of 

wheat, though great var- 
iation exists in both the 
quantity and the compo- 
sition of bran from dif- 
ferent kinds of wheat, 
owing to the varying de- 
grees of readiness with 
which the husks separate 
from the inner matter of 
the grain : in some cases 
the bran carries with it a 
considerable part of flour from within. Chemical an- 
alysis shows the bran to be richer in nutritive elements 
than is the interior flour; it is plain then that much 
valuable substance is lost from grain by the separation 
of the bran. 

Flour, — Whole-meal and Sifted. — The question 

as to the relative merits of sifted and of whole-meal 
flours has long been agitated. Certain it is that the 
superfine flours now in the market are sadly deficient 
in essential alimentary matters, which have been lost 
in the milling processes ; and the results of experiment 
and of experience indicate a preference for whole-meal 




Fig. 95, 
Part section of wheat grain. 



GRAINS AND BREAD. 807 

flour, though such should be ground fine. It is known 
that the husk of wheat is liable to produce derange- 
ment of the digestive organs because of its coarse, 
irritating nature* and its comparative insolubility. 
The nitrogenous parts of the bran are mostly located 
in the inner layers of the husk ; the outer layer of bran 
contains about 4.5 per cent, gluten; the inner part 
shows 18 per cent. It is therefore possible by remov- 
ing the outer layers only to increase the proportion of 
nutritive ingredients in the remaining meal, at the 
same time rendering the flour more readily digestible.! 
Flour is now attainable of many degrees of fineness, 
with corresponding variations in color ; the finest and 
whitest contain much starch, while the coarse and 
darker varieties show a larger amount of gluten and of 
mineral salts. It is plain then that the darker flours 
excel the superfine grades in nutritive value ; and that 
whiteness in flour cannot be properly considered an 
indication of superiority. 

Yeast, its Structure and Properties. — To pro- 



*" If the hu?k, which is demanded by the whole-meal agitators 
were as digestible as the inner flour they would unquestionably 
be right; but it is easy to show that it is not, and that in some 
eases the passage of the undigested particles may produce mis- 
chievous irritation in the intestinal canal. My own opinion on 
this subject * * * * is that a middle course is the 
right one, viz., that bread should be made of moderately dressed 
or 'seconds' flour, rather than overdressed 'firsts' or undressed 
'thirds,'— i. e., unsifted whole-meal flovir." Mattieu Williams. 

t "This removal of the outer flbrous coat involves a loss of about 
2 pounds in 100 pounds of grain. It may be accomplished by 
moistening the grain and rubbing it, or by the special process of 
milling known as decortication." Johnston. 



308 DOMESTIC SCIENCE. 

duce the soft, porous, spong}'^ bread, so justly esteemed 
as the basis of our foods, a quantity of yeast is com- 
monly incorporated with the flour. Ordinarily yeast 
appears as a murky liquid, with a bitterish taste and 
an odor that is suggestive of beer. On standing, 
bakers' yeast usually deposits a heavy sediment, which 
consists mostly of potato pulp and other vegetable 
matters added in the making. The purest and best 
yeast is the brewer's " barm," which is developed in 
the beer vats during fermentation. As an aid to our 
understanding of the use of yeast a few experiments 
should be made. If a small quantity of yeast be put 
into fresh fruit juice or any saccharine solution, and 
the mixture be kept at a proper temperature, bubbles 
of gas are soon evolved, and alcohol is formed, while 
the sugar of the liquid disappears. These changes are 
included under the general name of fermentation. 
The gas referred to may be collected and tested ; it will 
prove itself to be carbon dioxide. 

Now let us examine a drop of yeast microscopically. 
With a proper magnifying power, we shall find it to be 
a collection of small, oval bodies, distributed through 
a watery liquid (figure 96). If yeast be filtered so as 
to separate the tiny bodies from the liquid, the latter 
does not excite fermentation in sweetened fluids ; the 
corpuscles then are necessary to the efficacy of the 
yeast. If yeast be boiled, it loses its peculiar power 
of producing fermentative changes ; this seems to be 
for the same reason that cooked potatoes and peas have 
lost their power of germination — the heat has de- 
stroyed the vitality of the organism. If yeast be 



GRAINS AND BREAD. 



309 



added to pure water, it does not develop, because 
there is lack of food materials ; yeast so treated in 

reality starves to death. In 
a properly prepared solu- 
tion, however, the yeast 
rapidly increases, so that if 
but a few drops of yeast be 
added the whole liquid will 
soon be swarming with yeast 
organisms. The vitality of 
yeast is suspended at a low 
temperature ; this renders 

Fig. 96 




Yeast, as seen 



through the possible the preparation and 
microscope. use of "compressed yeast," 

which consists of yeast cells, freed from an excess of 
water, and preserved on ice in carefully wrapped pack- 
ages. These facts prove that the yeast corpuscles are 
in reality living organisms ; like other living things 
they grow in size and increase in numbers : they need 
food for their development ; they may be starved, or 
may be killed by temperature too high or too low. 
Careful observations warrant the conclusion that the 
yeast organism is in fact a plant belonging to the 
fungi : to which class also belong common mildews or 
molds, mushrooms, toadstools and the like. It lives 
and breathes essentially as do other plants, though it 
possesses peculiar habits of its own. The carbon 
dioxide and alcohol already referred to as products of 
yeast fermentation are indeed the exhaled breath of the 
plant. 

Doug^h. — When wheaten flour is well moistened, 



310 DOMESTIC SCIENCE. 

its particles cohere to form a soft, tenacious dough. If 
made from the best of flours; i. e., varieties rich in 
gluten, dough is very elastic and ductile ; admitting of 
ready molding and rolling into thin strips. Dough 
that consists only of flour mixed with water is poorly 
adapted for the making of bread, as when baked it 
becomes hard, dense and brittle. Let us inquire con- 
cerning the action of yeast in dough -making. The 
yeast is placed in the flour, with proper admixture of 
food materials, — potato pulp, hops, sugar, etc. ; the 
whole is then kept at a moderate temperature till fer- 
mentation begins, then flour and yeast are mixed, and 
thoroughly kneaded, by which process the yeast cells 
are distributed throughout the dough. Fermentation 
continues within the dough : the yeast plants thrive 
under the favorable condition of good food and proper 
temperature ; and they exhale much carbon dioxide 
and alcohol vapor. These gaseous emanations by their 
buoyancy strive to escape from the dough, and in so 
doing cause a pufiing of the latter, which results in a 
rising of the dough and the formation of a sponge. 

Baking" of Dough. — The dough is next to be 
molded and set in the oven ; there the gases expand 
under the influence of increased temperature ; much 
of the water present is converted into vapor, and adds 
to the buoyant effect ; as a result the bread "rises" 
and becomes still more porous and spongy. The 
dough is partially dried, and the walls around the 
pores become suflHciently rigid to permanently retain 
their position and shape. When the temperature has 



GRAINS AND BKKAD. 311 

risen sufficiently, the yeast plants are killed and the 
fermentation is consequently stopped at the proper 
stage. The best temperature for bread baking is 
about 450° F. ; this heat would completely char dry 
flour;* but evaporation of water from the dough 
takes place as the baking proceeds, and this renders 
latent much of the heat, and prevents a burning of the 
dough. Inside the loaf the temperature seldom far 
exceeds that of boiling water. The outer parts of the 
loaf are more highly heated than are the inner ; in 
consequence a surrounding shell or crust is formed. 
In this crust much of the starch has been converted 
into dextrin ; or if the loaf has been highly browned, 
some caramel may have been formed. Dextrin, it will 
be remembered, is soluble in water, and in some in- 
stances a glossy film of dextrin is found on the outside 
of the loaf. The crust possesses a slightly sweetish 
taste, and is more readily dissolved in the digestive 
fluids than is the crumb. 

Bread, New, and Stale. — Freshly baked or 
new bread is tenacious, soft and apparently moist; 
if kept some days after baking, however, bread be- 
comes hard, brittle, and seemingly much drier. Boussin- 
gault showed that the difference between new and stale 
bread is not entirely due to the drying process ; in 
demonstrating this he kept a very stale loaf in a heated 
oven for an hour ; during the operation the bread lost a 



* Some bakers test the temperature of the oven by throwing a 
little flour upon the floor. If this blackens at once the heat is 
satisfactory. 



312 DOMESTIC SCIENCE. 

q^uantity of moisture, becoming in reality drier, yet it 
came from the oven as a new loaf.* 

Baking" Powders.— Numerous substitutes for 
yeast in bread -making have been proposed; most of 
these are chemical mixtures, passing under the generic 
name of baking poivders. The principle upon which 
such preparations act to render dough spongy, may 
be illustrated by mixing a little baking soda with dilute 
hydrochloric acid. As soon as the substances come 
together a copious evolution of carbon dioxide occurs ; 
if such a liberation of gas should take place within the 
dough, it would cause the desired puffing and lighten- 
ing of the latter. A common preparation of the sort 
consists of sodium-bi carbonate, and hydrochloric acid, 
in the proportion of one ounce of soda, to nine fluid 
drachms acid ; these to be mixed with eight pounds of 
flour. Another product of the reaction between the 
acid and the soda, is sodium chloride or common salt, 
and as this is deyeloi3ed within the dough, and is 
therefore distributed throughout the mass, no other 
addition of salt is necessary in the process. 

Many common baking powders contain ammonium 
carbonate, which substance decomposes when exposed 
to heat, and forms gaseous ammonia, carbon dioxide, 



* "He [Boussingault] found that during the six days, while be- 
coming stale, it only lost one per cent, of its weight by drying; 
and that during the one hour in the oven it lost three and a half 
percent, in becoming new, and apparently more moist. By using 
an air tight case instead of an ordinary oven, he repeated the ex- 
periment several times in succession on the same piece of bread 
making it alternately stale and new each time." Williams. 



GRAINS AND BREAD. 313 

and vapor of water. These gases expand within the 
dough and produce a porous mass. The use of am- 
monium compounds is objected to for hygienic reasons ; 
yet baking powders of this sort are in commoner use 
than is generally supposed ; and a person may daily 
purchase of our city bakers fresh hot cakes and 
biscuits all strongly smelling of hartshorn. 

Alum Baking' Powders are considered objection- 
able by most hygienists. It has been proved that 
constant doses of alum will surely prove of detriment 
to health; though the quantity taken at a single eat- 
ing of alum bread is small. The chief reason for 
adding alum to dough, is to secure an increased 
whiteness in the bread ; this object it accomplishes 
admirably, though the mode of its operation is not 
well understood. The "rocky" used by British bak- 
ers consists, according to Tomlinson, of one part alum 
and three parts common salt. 

Aerated Bread. — Attempts have been made to 
introduce aerated bread to popular favor. To prepare 
this kind of bread, dough is made without admixture 
of yeast or baking powder ; this is then inflated and 
puffed by having air or carbon dioxide forced into it 
under high pressure. Bread so prepared has a pecu- 
liar "flat'' taste, not at all appreciated by most 
people. 

Barley and Rye. — Next to wheat, these claim our 
attention as food grains. These are both allied in 
composition to wheat. The following analyses by 
Poggaile are illustrative ; 



314 DOMESTIC SCIENCE. 





Barley. 


Rye. 




Per cent. 


Per cent 


Water . 


15.22 


15.53 


Albuminoids 


10.65 


8.79 


Starch, dextrin 


60.33 


65.53 


Fat 


2.38 


1.99 


Woody fibre . 


8.78 


6.38 


Ash 


2.62 


1.77 



Barley, though rich in nitrogenous matter, is de- 
ficient in true gluten, and is therefore not adapted for 
making dough. Hulled barley is the grain after the 
removal of its husk ; and pearl barley consists of the 
inner parts of the kernel only. Rye contains more 
saccharine matter than does either wheat or barley. 
Its bran possesses an aromatic flavor, which is 
appreciated by many. The nitrogenous matter of rye 
is closely allied to casein ; it has been called soluble 
gluten. 

Maize or Indian corn is rich in fatty matter, though, 
on the whole, it is less nutritious than is wheat. Its 
nitrogenous ingredient is peculiar ; unlike true gluten 
it is not adhesive, and corn bread in consequence 
crumbles readily. Compare the following analysis (by 
Poggaile) with the other analytical data already cited. 
Yellow maize contains : 





Per cent 


Water 


13.47 


Nitrogenous matter 


9.90 


Starch, dextrin, sugar 


64.53 


Fats 


6.68 


Woody Fibre and coloring matter 


3.97 


Ash 


1.44 



Corn meal readily spoils ; this is due to the ease 
with which the fatty matter undergoes oxidation. 
Crushed corn divested of its outer skin is known as 
hominv. 



GRAINS AND BREAD. 



315 



Oats are in some parts of the world more exten- 
sively used as food for men than in this country. In 
nutritive value, that is as a flesh producer, oat-flour 
excels all other grain preparations, Oats are rich in 
oily matter. Meal from oats is used mostly in por- 
ridge or gruel, though oat cakes are esteemed by those 
who have learned to know their merits. The follow- 
ing table represents the composition of dry oats ; it 
will be observed that the characteristic nitrogenous 
matter has received the special name, avenin (from 
avena, meaning oat) : 





Per cent 


Water .... 


14.3 


Avenin ^ 
Albumen > 
Gluten ) 


12.0 


Starch, sugar, gum 

Fat .... 


54.9 
6.0 


Woody fibre . 

Ash .... 


10.3 
3.0 



Buckwheat is highly nutritious, being in some 
respects almost equal to wheat. 

Rice differs from most other grains in being richer 
in starch, and more deficient in oil and nitrogenous 
matters. The albuminoids are not more than half as 
abundant as in oatmeal. Some samples of rice con- 
tain over 80 per cent, starch, though the average is 
lower. Johnston gives its composition as : 





Per cent. 


Water 


14.5 


Fibrin 


7.5 


Starch .... 


76.0 


Fat 


0.5 


Fibre .... 


1.0 


Ash .... 


0.5 



316 DOMESTIC SCIENCE. 

Sago, tapioca, arrowroot, are all rich in starch ; 
likewise are they easily digested, but are very incom- 
plete foods when eaten alone.* Nitrogenous and 
fatty matters should be added to them. 



REVIEW. 

1. Name the principal grains used as food for man. 

2. State what you know of the average composition of wheat. 

3 . Describe the structure of a wheat grain as revealed 'by 
the microscope. 

4. How is wheat prepared for use as human food ? 

5. Give reasons for your opinion as to the relative values of 
sifted and whole-meal flours. 

6. Explain the preparation of dough, 

7. What is the purpose of adding yeast in making dough? 

8. How is yeast prepared ? 

9. What does the microscope teach us respecting the nature 
of yeast ? 

10. What proof have you that yeast contains living organisms? 

11. Explain the " rising " of dough. 

12. Explain the changes taking place as dough is baked into 
bread. 

13. Describe the difference between crust and crumb of bread. 

14. Explain the difference between new and stale bread. 

15. What are baking powders ? 

16. What effect has a small amount of alum when mixed with 
dough ? 

17. What do you know of barley as food ? 

18. Of rye ? Of maize ? Of oats? Of buckwheat ? Of rice ? 

* Some people regard arrowroot, tapioca, and sago prepara- 
tions as admirable foods for invalids; and without doubt many a 
patient has been in danger of starving to death through this 
ignorance on the part of kindly-disposed nurses. Starch is not a 
tissue-forming food, and to be measurably nutritious such farina- 
ceous dishes should be enriched with good milk or eggs. Starchy 
foods are not adapted to the digestive conditions of infants. 



ANIMAL FOODS AND THEIR COOKERY. 317 



CHAPTER 32. 

ANIMAL FOODS AND THEIR COOKERY; MEAT AND EGGS. 

Flesh as Food. — All kinds of lean flesh are rich 
in nitrogenous ingredients, principally as myosin, 
fibrin, and albumen. Fresh meats contain a very 
large proportion of water ; lean beef is nearly 80 per 
cent, water. All meats, even the leanest, contain a 
considerable proportion of fat, which during the life 
of the animal existed within the body as oils. The 
following analysis (by Schurtz) of pure lean beef is 
instructive : 

Ter cent. 
Fibrin and myosin - - . . 15.0 

Albumen . _ . . _ 4.3 

Extractive matters, soluble in water - 1,8 

" alcohol 1.3 

Phosphates - . . . . traces 

Fat - - - - - * 0.1 

Water ---.-- 77.5 

This may be taken as a type of lean meats generally, 
though considerable variation exists among meats 
from different animals. Veal and venison are gener- 
erally deficient in fat ; pork on the other hand is ex- 
cessively oily. As a rule, the flesh of wild animals 
contains but little fat, whereas domesticated animals, 
even if in poor bodily condition, contain relatively 
much oily matter. The analysis quoted above is of 
pure lean muscle as free from fat as it was possible to 



318 DOMESTIC SCIENCE. 

procure the same ; ordinarily, however, meat contains 
several per cent, of fat ; of dry meat snbstance, fully 
one-fourth is fat. The flesh of birds generally con- 
tains less fat than does meat from quadrupeds, though 
some birds when kept in captivity may be artificially 
fattened. 

Fish of different kinds show varying contents of 
fat. The flesh of all fish is rich in albuminoids, and in 
mineral salts, especially phosphates ; some kinds, how- 
ever, as trout, whiting, sole, and carp are compara- 
tively poor in fats, while salmon, eels, and others are 
particularly rich in oil. 

Cookery of Meat — Seething".— As a rule, meats 

and fish in a fresh state are readily digested ; among 
meats, veal and pork are comparatively difficult to 
digest. Cooking is productive of many great changes 
in the condition of meat. If meat be immersed in cold 
water, much of its albumen and many of its sapid 
juices and mineral salts will be washed away, and 
little more-than the juiceless myosin will remain. If 
meat must be seethed (or as it is improperly said, 
"boiled") let it be done by immersing the flesh in 
boiling water at first ; the effect of this will be to 
harden the albumen in the superficial parts of the 
meat, and produce an outer protecting layer by which 
the inner juices will be retained. The cooking should 
then be completed at a lower temperature ; not above 
165° F. ; for it will be remembered that the heat of 
boiling water is effectual in hardening albumen into 
an indigestible mass. Under the best conditions, 
seething is a poor mode of cooking meat, except in 



ANIMAL FOODS AND THEER COOKERY. 319 

making stews, in which case the watery extract and 
the solid residue are eaten together.* 

The Water-bath. — To guard against undue heat, 
it is well to conduct the cooking of albumen in a 
steam -bath or water- bath. The essential features of 
the latter are represented in figure 97 ; -4 is an outer 
vessel, containing water, into which the cooking- re- 
ceptacle, -B, is fitted. The contents of B will not be 
raised to the full temperature of boiling water. 

Soup-making'. — in the preparation of soups, 
however, an opposite course from that designed to 
retain the juices is indicated. In such a case it is de- 

^ sirable to extract the meat 
<^^^^^gg/^ ^^ juices and this is best done 

^^r=u.J ^ JllillK ^y subjecting meat in a 

^^^ ., JK^Bj minced state, to the action 

"^^ _ \^g^P -^=r of cold Avater, the result- 

Fig. 97. ing extract of meat may be 

Water-bath. afterward heated and flav- 

ored. The heating, however, should be carefully reg- 
ulated, else the temperature may rise to the point of 
coagulation of the contained albumen, which will then 
separate in shreds or flakes, and the careful cook will 
be sure to remove these floating bits, and thus will 
lose some very valuable material. Myosin or animal 



*"It should be boiled only for a few minutes, and then kept 
for some time at a temperature from 158° to 165°. Meat is under- 
done or bloody when it has been heated throughout only to the 
temperature of coagulating albumen (140°) ; it is quite done or 
cooked when it has been heated through its whole mass to 158° or 
165°, at which temperature the coloring matter of the blood coag- 
luates." YouMANS. 



320 DOMESTIC SCIENCE. 

fibrin is practically insoluble in cold water ; it is 
therefore impossible to extract it by maceration, and 
although treatment with cold water will remove most 
of the sapid constituents of the meat, together with 
some gelatin and mineral salts, leaving only a fibrous 
residue which is almost tasteless, and if eaten alone, 
actually nauseating, still the extract -without the fibre 
is a very poor diet. Many sick people have been 
almost starved on a beef tea regimen.* All kinds of 
meat extracts, of which there are many now in the 
markets, are deceptive as to their true nutritive value. 
Roasting" if properly conducted will produce far 
better results than are possible in seething. In the 
roasting process, meat should be exposed at the be- 
ginning to an intense heat, — the best effects are ob- 
tained from an initial temperature of 400° F. ; by 
such means the surface albumen is hardened, and an 
impervious layer is formed about the inner parts in 
which the juices are held. This temperature should 
be maintained for a short time — for small joints about 



* Dr. Martin says of beef tea: — " The flavoring matters make it de- 
ceptively taste as if it were a strong solution of the whole meat, 
whereas it contains but a small proportion of the really nutritious 
parts, which are chiefly left behind in tasteless shrunken shreds 
when the liquid is poured off. Some things dissolved out of the 
meat make beef tea a slight stimulant, but its really nutritive 
value is small, and it cannot be relied upon to keep up a sick per- 
son's strength for any length of time. Liebig's extract of meat 
is essentially but a concentrated beef tea; from its stimulating 
effect it is often useful to persons in feeble health, but other food 
should be given with it. It contains all the flavoring matters of 
the meat, and its proper use is for making gravies and flavoring 
soups, the erroneousness of the common belief that it is a highly 
nutritious food cannot be too strongly insisted upon, as sick per- 
sons may be starved on it if ignorantly used." 



ANIMAL FOODS AND THEIR COOKERY. 3 21 

one -sixth of the entire time required for complete 
roasting, — the heat should then be reduced and the 
subsequent cooking allowed to proceed at 200° F. 
The gravy of roasted meat consists of melted fat and 
some juice that has found its way out of the joint. 

In baking meats, a vessel of water should be set in 
the oven that the heated air may be well supplied with 
liquid ; else as its capacity for moisture increases with 
the rising temperature it will absorb the fluid parts of 
the meat and produce a disagreeable dryness of the 
joint. By the old-time style of spit roasting, it was 
necessary to constantly baste the meat by pouring 
melted fat over the surface, otherwise a deplorable 
loss of juice would have occurred. Such fish as is 
naturally poor in oil should be coated with grease 
during the cooking operation, to aid in the retention 
of its juices. 

Broiling" or Grilling" is a common method of 
cooking small pieces of meat, such as steaks, chops, 
and cutlets. The meat should be exposed to the high 
heat of a bright aud smokeless fire ; the result will be 
a rich, juicy morsel ; whereas slow cooking will pro- 
duce a dried ill -flavored piece, alike unattractive to 
eye and palate. 

Frying, among all common operations of cooking 
is perhaps the most objectionable from a hygienic 
point of view. As ordinarily performed, the frying 
process consists of smearing a thin layer of fat on 
the bottom of a frying-pan, placing therein the thing 
to be cooked — say for example a piece of meat — and 
heating the whole over a fire. But one side of the 



322 



DOMESTIC SCIENCE. 



piece will be heated at a time, and though the under 
surface may be browned, the upper side remains un- 
cooked long enough to allow the escape of Juices from 
within. Some fat will be absorbed by the meat, and 
the fibres becoming thus coated will resist the subse- 
quent action of the digestive fluids. The great mistake 
in ordinary frying lies in proceeding as if the cooking 
depended upon direct conduction of heat from the fire 
through the iron floor of the pan to the meat, the fat 
being regarded as useful only in preventing the meat 
from sticking to the metal. The fat should be suffi- 
ciently abundant to envelop and surround the meat, 
as by such method only can heat be communicated 

uniformly on all sides. 
Good cooks are now 
abandoning the frying 
pan for the frying kettle ; 
an illustration of the lat- 
ter device is here repro- 
^.. ^„ duced (figure 98, after 

Fig. 98. \ to ' 

Frying kettle. Gouffe). The vessel is a 

deep one ; a movable tray of coarse -mesh wire (shown 
here removed) rests within an inch or two of the bot- 
tom. Sufficient fat is placed within to completely 
cover this tray when the latter is in position. The fat 
is highly heated, and the thing to be cooked is then 
placed upon the wire support, completely immersed in 
the oily bath. The effect of this method is to heat the 
object on all sides, and to retain most of its juices. 
Contrary to ordinary expectation, experiment shows 
that such a bath of fat may be used for fish, meats, 




ANIMAL IfUODS AND THEIH COOKEUY. 323 

vegetables, and fruits in succession, without communi- 
cating the flavor of one to the others. The employ- 
ment of so large a quantity of fat is not as extravagant 
as vrould at first thought appear, as less is absorbed 
by this process than by the greased pan method. When 
necessary, the fat may be purified by removing its 
suspended particles which readily separate as sediment 
or scum. 

Eg'g'S constitute an important item of animal food. 
Those of domestic fowls, ducks, geese, and turkeys 
are commonly used. An examination of an egg will 
show it to consist of shell, white, and yolk. Of these 
the shell is discarded from food, the other parts are 
eaten. The white of egg is almost pure albumen ; the 
yolk consists mainly of water, albumen, and a peculiar 
oil, bright yellow in color and containing compounds 
of sulphur and phosphorus. This oil forms nearly 
two -thirds by weight of the perfectly dry yolk. The 
fat of the egg is concentrated in the yolk, the white 
being poorly supplied with oily matter. The compo- 
sition of eggs, exclusive of shell, will be understood 
from the following table (Johnston). 







White. 


Yolk. 


Whole egg. 






Per cent. 


Per cent. 


Per cent. 


Water . 


. 


85 


51.5 


71.75 


Albumen 


. 


12 


15 


14 


Fat, etc. 


. 


2 


32 


13 


Phosphates, 


etc. 


1 


15 


1.25 



In cooking eggs it should be remembered that the 
albumen is completely coagulated at a temperature 
below 160° F. ; and any higher heat will harden the 
substance. The old-time method of cooking eggs in 



324 DOMESTIC SCIENCE. 

the shells was to keep them in boiling water for three 
minutes; " egg timers" were made on the principle 
of the hour glass ; as soon as the eggs were immersed 
the glass was turned, and when the sand had run its 
course the eggs were considered done. A better 
method consists in placing the eggs in water that is 
near the boiling temperature, allowing about a pint 
of water to each egg. The eggs will share the heat 
of the water and the temperature will be reduced to 
the required degree, and the cooking will proceed 
without danger of over-heating. The vessel con- 
taining the water and eggs should of course be set 
aside from the fire ; the eggs cannot become hard even 
by prolonged exposure to water below 160° F. 



REVIEW. 

1. State what you know of the relative food values of some 
common meats. 

2. What is the effect of placing lean meat in cold water ? 

3. What is the effect of hot water on lean meat? 

4. What do we learn from these facts, as to the proper 
means of cooking meat ? 

5. Describe the water-bath. 

6. Of what value is the water- bath in cooking ? 

7. What is meant by seething meat ? 

8. What do you know of the value of beef tea as a diet for 
invalids ? 

9. Explain the changes taking place in the roasting of meat. 

10. Explain the difference between roasting and baking meats. 

11. Explain the process of broiling meat. 

12. Describe the ordinary method of frying. 

13. Show the use of the frying kettle. 

14. What do you know of eggs as food ? 

15. What is the proper cooking temperature for eggs ? 



MII.K, BUTTER, AND CHEESE. 



325 



CHAPTER 33. 

ANIMAL FOODS CONTINUED ; MILK, BUTTER, AND CHEESE. 

Milk constitutes the sole food of infants and of the 
young of mail)' animals ; this fact is proof of its nu- 
tritive value. Chemically, milk consists of a large 
proportion of water in which is dissolved sugar, casein, 
and mineral salts, while oil or butter particles are 
suspended in the fluid. The following table repre- 
sents the mean composition of milk from different 
sources : 





Cow 


Goat 


Ewe 


Human 
Milk 


Water 


87.02 


86.80 


85.62 


88.90 


Casein (curd) 


4.48 


4.08 


4.50 


3.90 


Fat (butter) 
Sugar of milk 


3.13 
4.77 


3.32 
5.28 


4.20 
5.00 


2.67 
4.36 


Saline matter 


.60 


.52 


.68 


.14 



A drop of milk, when viewed through the micro- 
scope, appears as a collection of many floating globules ; 

such a view is rep- 
resented in figure 99. 
Milk, therefore, is 
both a solution and 
an emulsion. 'New 
milk is slightly alka- 
line ; this property 
assists in keeping 
the fat globules in 
suspension. Oil and 
pure water may be 
Milk viewed through the microscope. agitated together, 




326 DOMESTIC SCIENCE. 

yet as soon as the liquids come to rest they separate ; 
but if the liquid be first rendered slightly alkaline, the 
oil by shaking will become more finely divided, and 
part of it will be permanently distributed through the 
water. As milk sours it becomes less able to hold fat 
globules in suspension. 

Milk is used in its raw state, though boiled milk 
is a constituent of many prepared dishes. In boiling, 
the albumen of milk coagulates and appears upon the 
surface as a scum ; this coagulum is impervious to 
steam, consequently vapor cannot readily rise from 
the heated liquid, and the milk "boils over" if the 
heat be continued. All milk of unassured wholesome- 
ness should be boiled before being used, as a precau- 
tion against the possible communication of disease 
germs. Many contagious diseases have been spread 
through the medium of impure milk. 

Milk is a nutritious food, though it is not adapted as 
the sole aliment of adults. It is a common supposi- 
tion that milk is apt to produce troubles of indiges- 
tion ; yet children live upon it while their digestive 
organs are still weak. Ill results are likely to follow 
the rapid drinking of large quantities of milk, because 
the liquid curdles in the stomach, and if it be unmixed 
with gastric juice, its assimilation within the body will 
be long delayed. Milk should be drunk slowly ; it 
should be sipped only, so as to imitate in some degree 
the natural method of swallowing milk directly from 
the lacteal glands. If milk be used as a beverage, a 
corresponding diminution in other animal foods should 



MILK, BUTTER, AND CHEESE. 327 

be made, else the consumer may suffer from over-nu- 
trition. 

Cream. — The fat globules of milk are lighter than 
the rest of the fluid ; consequently they rise and form 
upon the surface an oily layer, which is mingled with 
considerable casein or cheesy matter, and constitutes 
the cream. Not all the fat so rises, considerable 
still remains in "skim milk." The larger globules of 
fat rise first, and the cream that first forms is richer 
than that which appears subsequently ; the dairy 
custom of skimming milk twice is a good one, as 
thereby may be obtained a quantity of richer and 
better flavored cream. Fat globules cannot readily 
rise from great depths of liquid ; it is therefore custo- 
mary to set milk in shallow pans till the cream has 
risen. In large dairies it is now customary to employ 
mechanical separators, whereby the cream is rapidly 
removed from the milk without the long interval of 
setting. 

Butter. — By churning, the fat globules of milk are 
brought together to form butter. Most of the water, 
casein, and mineral salts remain in the butter-milk. 
As ordinarily made butter contains about 10 per cent, 
water, 2 per cent, casein (or curd), milk-sugar, and 
salt, and about 88 per cent. fats. It possesses in 
addition to these certain aromatic compounds of 
butyric acid, to which the peculiar flavor of fresh 
butter is due. Inferior butters contain much water 
and salt. 

Many so-called Artificial Butters have of late 
years been manufactured under the names of margar- 



328 DOMESTIC SCIENCE. 

ine^ oleo -margarine, and butterine. These substances 
consist of soft animal fats mingled with true butter. 
In the preparation of such, animal suets are minced, 
heated and pressed, so as to yield their softer portions 
in a liquid state ; this oily matter is then filtered, 
mixed with milk, and churned. As a rule these 
adulterated butters are manufactured with care and 
cleanliness ; only good fats are used in the process, 
and both chemically and physiologically such prepara- 
tions are as wholesome and almost as nutritious as is 
true butter. It is no less a deception, however to sell 
them under the name of butter. Instead of seeking 
by legislative enactment to forbid the manufacture and 
sale of imitation butters, it would seem wiser to enact 
laws requiring such products to be sold under their 
true names and at a fair price.* 

Cheese may be regarded as the pressed and salted 
casein of milk. Milk may be curdled in many ways. 
If left to itself it undergoes the change spontaneously ; 
a^cid may be artificially added to produce curd ; but the 
best method of causing coagulation is by the addition 
of rennet, which consists of the salted stomach of a 
sucking calf or pig. As the casein coagulates, it takes 
with it a considerable amount of fat, together with some 
sugar and water, leaving most of the water, sugar, and 
mineral compounds in the whey. In precipitating 
curd by acid, many mineral ingredients are lost in the 

*The author has analyzed and practically tested many artificial 
butters, and he is convinced that good oleomargarine is far pre. 
ferable in flavor and wholesomeness to inferior butter; yet he is 
none the less disgusted that he has had to pay butter prices for 
that which was not butter. 



Milk, butteu, and cHEKsli. 52§ 

whey, whereas by the use of rennet they are retained 
in the curd.* Cheese is sometimes made from cream ; 
such cheese is of a very oily nature and is prone to 
rapid decomposition. Cheese made from unskimmed 
milk is considered best; though that made from 
skimmed milk is rich in casein, but deficient in fats. 
The following table (by Johnston) represents the rela- 
tive composition of whole milk and skimmed milk 
cheese : 

Cheddar, whole Skim milk 
milk cheese. cheese. 





Per cent. 


Per cent. 


Water 


36 


44 


Curd or casein 


29 


45 


Milk fat - 


80.5 


6 


Salt and phosphates 


4.5 


5 



As a food, cheese is not generally appreciated ac- 
cording to its merits. It contains fully twice as much 
nutritive solid matter as does the best selected meats. 
Cheese is by many considered to be difficult of diges- 
tion and generally productive of ill results. Un- 
doubtedly if eaten in large quantity, in addition to 
other highly nutritive foods, the bad effects of exces- 
sive nutrition will be manifested. Cheese should be 
used to supplant, not simply to supplement, other 
animal foods. By proper cooking, cheese may be 
rendered easy of digestion. f 



* " Casein that has not been treated with acids contains about 6 
per cent, of phosphate of lime." Lehmann. 

t Mr. Mattieu V7illiams, of London, has reported many trials 
upon the relative merits of raw and of cooked cheese. He says: 
" I may here mention that I have recently made some experi- 
ments on the dissolving of cheese, by adding suflScient alkali 
11 



330 DOMESTIC SCIENCE. 

REVIEW. 

1. State what you know of the nutritive value of milk. 

2. Describe the microscopical appearance of milk. 

3. Explain the changes effected in milk by boiling it. 

4. Explain the rising of cream. 

5. Explain the process of churning. 

6. What do you know of artificial butters ? 

7. What is cheese ? 

8. By which two methods may the casein of milk be coagu- 
lated in the manufacture of cheese, 

9. What advantage belongs to either of these methods over 
the other ? 

10. Compare the nutritive value of whole milk cheese, with 
that of skim-milk cheese. 

11. State your opinion of cheese as a food. 

(carbonate of potash) to neutralize the acid it contains, in order 
to convert tlie casein into its orij^inal soluble form as it existed in 
the milk, and have partially succeeded both with water and milk 
as solvents. 



SOME AUXILIARY FOODS. 331 



CHAPTER 34. 

SOME AUXILIARY FOODS. 

Beside the classes of true foods already referred to, 
there are certain substances which are commonly used 
in diet, not for their nutritive worth, but to impart 
attractive flavors to regular food. These are some- 
times called condiments, 

Vineg'aP is one of the commonest of condiments. 
It is produced by the acetous fermentation of sac- 
charine solutions and fruit juices, such as cider and 
wine. Its essential ingredient is aceti'3 acid, of which 
ordinary vinegar contains about four per cent. Com- 
mercial vinegars vary greatly in strength ; however, 
the so-called "proof" vinegar contains 4.6 per cent, 
acetic acid. According to their source and mode of 
preparation, common vinegars are described as malt 
vinegar, spirit vinegar, cider vinegar, and wine vine- 
gar. Aromatic vinegars are artificially flavored and 
perfumed. It is generally believed that small quanti- 
ties of vinegar may aid digestion by increasing the 
solvent power of juices within the stomach. Many 
albuminoid matters are partially soluble in dilute 
acetic acid. 

Vinegar from fruit juices usually possesses a peculiar 
aroma indicative of its source. AVhite vinegar is with- 
out aroma ; it is a simple mixture of acetic acid and 
water, and may be cheaply prepared by adding pure 
acetic acid to water to produce the required degree of 



332 DOMESTIC SCIENCE. 

acidity. If the absence of color be an objection, a 
very rich tint may be imparted by adding a little cara- 
mel or burnt sugar. Occasionally vinegar is adulter- 
ated with sulphuric acid ; this is an injurious addition, 
and a competent chemist will readily detect the presence 
of the poisonous acid in any sample. 

Pickles are prepared by treating various vegetable 
products with brine and vinegar. They are used 
solely as condiments. If eaten in large quantity, 
pickles will certainly prove of detriment to the body. 
Pickling operations should be conducted in vessels of 
porcelain, stoneware or glass only. Acetic acid will 
attack metallic vessels, and form poisonous salts. The 
bright tints so much admired in bottled pickles are fre- 
quently due to the deadly copper acetate, formed by the 
action of pickling fluids on copper or brass kettles 
used in the process. 

Lemon, and Lime Juices are sometimes used as 

substitutes for vinegar. AVhen mixed with water, they 
form agreeable beverages. Both substances are rich 
in citric acid, sometimes containing as high as 30 
grains of acid to the fluid ounce of juice. A moderate 
quantity of these substances is of decided benefit to 
the body ; they are of medicinal effect in counteracting 
any tendency to scorbutic diseases. By the use of lime 
juice, scurvy has been checked among Arctic naviga- 
tors who have been long confined to a salt meat diet. 

Certain Essential Oils are used for flavoring 

purposes; such are oil or essence of lemon, orange, 
vanilla, nutmeg, banana, pine apple, etc. In larg.e 
doses all of these substances are active poisons, but 



SOME AUXILIARY FOODS. 333 

the amount ordinarily employed is so very small that 
no serious result need be feared from their occasional 
use. Many of the essential oils are largely and some 
injuriously adulterated, however. 

Spices and other aromatic compounds are also in 
common use as condiments. Among such may be 
named pepper, black and red ; mustard and cloves in 
the plain state, or prepared in sauces ; horse radish, 
and many other substances. Savory herbs may be 
advantageously substituted for more stimulating con- 
diments ; thyme, parsley, sage, sweet majoram, and 
mint, are in common and beneficial use. 

Salt, though in some sense a condiment, is still an 
essential ingredient of food.* It has received atten- 
tion in a former chapter. (See page 262.) 

Dang-ep from Condiments.— Danger attends the 

frequent eating of stimulating condiments ; the diges- 
tive organs may be so habituated to the presence of 
such substances, that plain food seems insipid. The 
general effect of highly seasoned food is to produce an 
irritation of the intestinal tract, with strongly marked 
nervous affections, t 



*"Hard work and attendant good appetite require little else 
than common salt as a condiment, which should be plentifully 
used. It was said by Plutarch that hunger and salt were the only 
sauces known to the ancients, and the very word ' sauce,' is 
derived from the Latin word szdsiis, salted.' " — McSherry. 

+ Dr. Beaumont says: "Condiments, particularly those of the 
spicy kinds, are not essential to the process of digestion, in a 
healthy state of the system. They afford no nutrition. Though 
they may assist the action of a debilitated stomach for a time, 
their continual use never fails to produce a weakness of that 
organ. They affect it as alcohol or other stimulants do :— the 
present relief afforded is at the expense of future suffering." 



334 DOMESTIC SCIENCE. 

Certain Aptifieial Drinks, may with propriety 

be classed under the title of auxiliary foods. All 
beverages other thau water or milk, may be so re- 
garded ; though we would best exclude from the list 
alcoholic liquors of all kinds ; none of which, from a 
chemical or a physiological standpoint, can properly 
be classed as foods, except by reason of the small pro- 
portion of sugar and extractive matters which they 
contain. Alcohol, though consisting of carbon, 
hydrogen, and oxygen, is not digested or assimilated 
within the body. Liebig, the noted chemist, declared 
that the small quantity of flour, which can be picked 
up upon the point of a knife, contains more nutriment 
than two gallons of the best beer. 

Tea as ordinarily prepared, is an infusion of the 
dried leaves of the tea plant, a small shrub which is 
grown mostly in China. Under cultivation, the plant 
grows from three to six feet in height, and reaches 
maturity in two years ; it yields three crops of leaves 
per year. The first crop of the season furnishes the 
youngest, tenderest, and most fragrant leaves. The 
tea leaves are gathered by hand ; while fresh, they 
possess none of the fragrance of dried leaves. They 
are subjected to a complicated roasting in open vessels 
with frequent shaking and rolling; by this process 
some water is expelled, the color of the leaves is 
changed, and their aromatic properties are developed. 
The difference between green and black tea is mainly 
dependent on the preparation, though some choice is 
indicated as to the species best suited for one kind or 
the other. 



SOME AUXILIARY FOODS. 335 

Chemical analysis shows tea to contain a volatile oil, 
theine, tannin, and gluten. The oil of tea is volatile, 
and strongly aromatic ; to it is largely due the flavor 
of tea. The potent properties of this substance are 
illustrated by the fact that a hundred pounds of leaves 
contain less than half a pound of the oil. Its effect 
upon the human system is shown in nervous disor- 
ders ; and in the separated state it is known to be a 
powerful poison. Tea drinkers, professional tea- 
tasters, and especially packers of tea leaves, are subject 
to headaches, giddiness, and in severe cases even 
paralysis. Theine is a white, crystalized solid which 
may be readily sublimed from dried tea leaves. It 
belongs to the chemical family of alkaloids, all of 
which are of a poisonous nature. In small doses, it 
stimulates the body, and to its action is due the de- 
ceptive feeling of increased strength to the habitual 
tea- drinker. Teas of medium quality contain from 2 
to 3 per cent., and exceptional samples have shown, 
even 6 per cent, of the alkaloid. Tannin is the 
astringent principle of tea ; the substance is so named 
from its abundant occurrence in oak bark, which is 
used in tanning. Tannin and tannic acid produce 
inky infusions with water containing iron. It aids in 
producing the stimulating effect which usually follows 
an indulgence in tea drinking. Gluten is present in 
tea to the extent of 20 to 25 per cent. As the sub- 
stance is insoluble in water, it is not extracted in the 
infusion, but is lost in the dregs. 

The infusion of tea contains the soluble matter, in- 
cluding the tannin and volatile oil. If the steeping be 



336 DOMESTIC SCIENCE. 

done in a closed vessel, a very fragrant liquid results. 
The tannin is extracted after long steeping; the vola- 
tile oil, however, is expelled by prolonged heating; to 
procure at once a fragrant and strong infusion, two 
lots of leaves should be steeped, — one for a few 
minutes only, the other for a longer time ; the two 
infusions should then be mixed. 

Coffee is an infusion of certain roasted seeds, the 
commonest being derived from the coffee tree. In a 
cultivated state this tree reaches a height of 6 to 10 
feet. The seeds are very improperly called " coffee 
beans" and '' coffee berries." The best quality is 
Mocha coffee, then follow, in order, the coffees of 
Java, East India, Ceylon, and Brazil. Coffee seeds 
contain a volatile aromatic oil. This is present in 
such small quantity that 50,000 pounds of the coffee 
seeds would yield but one pound of the oil. Payen 
says the oil could not be prepared and sold at a lower 
cost than $500 an ounce. Coffee seeds contain also 
gluten ; an alkaloid known as caffeine, now supposed 
'to be identical with theine, and an astringent principle 
caffeo- tannic acid, analogous in properties to the cor- 
responding ingredients of tea. 

Tea and Coffee Drinking". — The general effect 

of tea and coffee is to produce a stimulation of the 
nervous system, which is followed by a reactive de- 
pression. Long continued indulgences produce 
specific derangements to which the name " tea disease" 
has been applied. The custom among students of 
drinking coffee to keep them awake is suicidal. The 
system may be habituated to these as to any other 



SOME AUXILIARY FOODS. 33 

stimulants, and when their use is discontinued serious 
discomfort results.* The habit is an enslaving one : 
it makes man dependent on drugs for the exercise of 
his powers. Such habits are cords that bind mind and 
body in the discharge of their functions. The sub- 
stances are potent medicines, and should be used with 
great wisdom. As indulgences they are not good for 
the body. 

Cocoa and Chocolate are prepared from the 
cocoa or cacao seed, which is produced in South 
America, and the West Indies. These seeds are par- 
ticularly rich in fatty matter, to which is given the 
name cocoa butter. This exists in the bean to the 
extent of over 50 per cent. An alkaloid body is pre- 
sent in the beans; this is called theobromine it is 
similar in properties to theine. The ground beans, 
sometimes mixed with sugar, and often fraudulently 
adulterated with starch and flour, etc., compose cocoa. 
If the product be flavored and seasoned, it is called 
chocolate. Cocoa and chocolate as prepared for the 
table, are not mere infusions, but rather in the nature 
of soups or gruels. All the nutriment of the solid 
therefore enters the body. All the prepared cocoas 

*"I recommend tea drinkers who desire to practically investi- 
gate the subject for themselves, to repeat the experiment I have 
made. After establishing the habit of taking tea at a particular 
hour, suddenly relinquish it altogether. The result will be more 
or less unpleasant; in some cases seriously so. My symptoms 
were a dull headache and intellectual sluggishness during the 
remainder of the day,— and if compelled to do any brain work, 
such as lecturing or writing, I did it badly. This, as I have already 
said, is the diaeased condition induced by the habit. These 
symptoms vary with the amount of the customary indulgence, 
and the temperament of the individual." — Williams. 



338 DOMESTIC SCIENCE. 

and chocolates of the market are largely adulterated,* 
and the proportion of active ingredients introduced 
into the body by drinking the beverage is correspond- 
ingly diminished. The pure cocoa bean would exert 
stimulating and narcotic effects analogous to those 
resulting from the use of tea or coffee. 



REVIEW. 

1. What is meant by auxiliary foods ? 

2. Define "condiments." 

3. Name the principal condiments in common use. 

4. What is vinegar ? 

5. Describe briefly the preparation of vinegar. 

6. What do you know of the strength of commercial 
vinegars ? 

7. What special characteristic is possessed by fruit vinegars? 

8. Explain the preparation of pickles. 

9. What precautions should be taken as to the material of 
the vessels in which pickles are made and kept ? 

10. What do you know of lemon and lime juices as condiments 
or as ingredients of beverages? 

11. Name the principal essential oils used as flavors. 

12. What do you know of salt as a condiment ? 

13. Name the principal artificial drinks that are used as 
auxiliary foods. 

14. Describe the growth and preparation of tea. 

15. What do you know of the chemical composition of tea ? 

16. State the properties of the volatile oil of tea. 

1 , ^ 

* The eoninion adulterants of cocoa are often of a disgusting 
kind. The following is on the authority of Dr. Youmans who 
quotes from Normandy: " I have known cocoa powder made out 
of potato starch moistened with a decoction of cocoa-nut shells 
and sweetened with molasses; chocolate made of the same 
material with the addition of tallow and ochre— a coarse paint. I 
have also met with chocolate in which brick dust or red ochre 
had been introduced to the extent of 12 per cent." 



SOME AUXILIARY FOODS. 339 

17. Of theine. 

18. Of tannin. 

19. State what you know of the growth of the coffee plant. 

20. What do you know of the volatile oil of coffee ? 

21. What is the source of the cocoa of commerce ? 

22. What is the difference between cocoa and chocolate ? 

23. What do you know of the common adulterants of cocoa ? 

24. State the general physiological effects of tea or coffee 
drinking. 



340 DOMESTIC SCIENCE. 



CHAPTER 35. 

PRESERVATION OF FOOD STUFFS. 

Decay of Organic Matters. — All organic matters, 

to which class of substances our ordinary food stuffs 
belong, easily undergo decay. In this process certain 
of their elements are separated and then re -combined 
in different proportions, producing compounds entirely 
unlike the original. Were it not for such ability of 
ready change, easy digestion of foods would be 
impossible, for this bodily process is one of 
change in which new and strange products are 
formed from the elements of food. With nitro- 
genous compounds, the process of decomposition is 
known as putrefaction, and the products are usually 
disgusting to our senses. Decomposition and re-com- 
position changes of a less disagreeable nature, espec- 
ially such as occur in carbohydrates, are spoken of as 
fermentation. From very early times, man has striven 
to devise a method of preserving food by artificial 
means, so as to prevent these destructive changes. 
Let us first consider the nature of the decomposition 
process. 

Bacteria and Decay. — Whenever putrefaction of 
organic matter is in progress, the microscope reveals 
within the substance the presence of many tiny forms of 
life, the chief appearances of which are shown in 
figure 100. These tiny organisms have received the 



PRESERVATION OF FOOD STUFFS. 



341 



generic name of bacteria^ from a word meaning little 
rod or staff, and so applied because of the rod -like 
shape of the typical and commonest form. The 
bacteria are known to belong to the kingdom of 
plants, and to the order of fungi ; they are, therefore, 

closely related to the yeast 
plant. A discussion has 
been indulged in among 
scientists, as to whether 
the presence of bacteria is 
the cause of decay, or de- 
cay the cause of bacteria 
being present ; we may 
leave the contestants to 
their own dispute and ac- 
cept these facts, which 
both parties admit, that 
spontaneous decay of or- 
ganic matter is not known 
to occur unless such organ- 
isms are present; and, farther, that any method by 
which these tiny structures may be excluded or killed, 
will arrest or prevent putrefaction. 

Freezing" constitutes a time -honored mode of pre- 
serving food substances. It is well known that decay 
is more rapid in summer than in winter ; and this is 
perhaps partly due to the inactivity of bacteria at low 
temperatures. Perishable foods are usually kept on 
ice ; refrigerators or ice boxes are now in common use 
for this purpose. Carcasses of sheep and cattle are 
shipped in a frozen state from Australia and New 




Fig. 100. 

Bacteria. 
(Very highly magnified.) 



342 DOMESTIC SCIENCE. 

Zealand to Europe, and the meat is eaten months after 
the time of death.* Chemical analysis fails to reveal 
any objectionable properties in frozen meat, though 
practical experience demonstrates a great superiority 
of fresh flesh over preserved meats of any kind. 

Canning", Bottling', etc. — Food stuffs are often 
preserved by hermetic sealing in cases. Meats are 
usually kept in cans ; fruits in bottles. In canning or 
bottling, the food material is placed in the vessels and 
heated to the boiling point of water, in order to des- 
troy the bacteria present ; the cans are then securely 
closed by having the tops soldered in place, and the 
bottles are closed by tightly fitting screw-lids. If the 
process be thorough, all bacterial organisms there 
present being killed, and others prevented from gain- 
ing access, no decomposition will take place. It has 
long been supposed that this preservative effect is due 
to the exclusion of air, and that oxygen is the chief 
agent of putrefactive changes. It is true that the 
chemical changes of decay are processes of oxidation ; 
but that spontaneous decomposition is closely as- 
sociated with bacterial life is equally certain. Prof. 
Tyndal |and other eminent experimenters have con- 
clusively shown that air thoroughly cleansed from all 

* As an example of the prolonged preservation of flesh through 
the agency of ice, consider the following; "In the year 1799 a 
Siberian fisherman saw a rounded mass projecting from an ice 
bank near the mouth of the rive Lena. The summer weather 
so thawed it year after year, that in 1803 the enveloping ice was all 
melted and the nucleus of this mound-like projection was found 
to be an enormous elephant (known as the mammoth). Though 
it had been there not merely centuries, but ages, it was perfectly 
preserved, so that dogs and wolves fed upon it as upon fresh 
meat." Hooker. 



PKESERVATION OF FOOD STUFFS. 343 

ger7ns of life may be freely admitted to perishable 
articles without causing decomposition. Air may be 
so cleansed in many ways, by being passed through a 
heated tube, thus burning to death the bacterial or- 
ganisms ; or by thoroughly washing by means of a 
spray of water, by which the organisms will be 
stopped ; or by being strained through a thick filter of 
cotton fibre. The writer can personally vouch for the 
reliability of the method of securing bottled fruits by 
tying tightly a thick layer of cotton batting over the 
mouth in place of the ordinary screw-top. Through 
this fibrous cap the air can make its way with ease, 
but all solid particles, both living and dead, will be . 
stopped. As bottles and cans of fruit are ordinarily 
sealed at the boiling temperature, there is a shrinkage 
of the contents as cooling proceeds, and a consequent 
tendency of the outer air to force an entrance. This 
outside pressure will depress the top of a well -sealed 
can ; but if fermentative changes have taken place 
within, the accumulation of gas will cause a bulging 
of the top and bottom. Beware of such over -filled 
cans, their contents are spoiled. 

Mineral Poisons in Canned Goods.— The use of 

canned foods is fraught with danger from the fact that 
poisonous compounds are often formed by the action 
of the juices upon the metal of the can ; and such are 
sometimes derived from the solder and the soldering 
fluids. Tinned ware is often adulterated with lead; 
and cases of lead -poisoning are not infrequent among 
the users of canned goods. Zinc chloride (butter of 
zinc) is largely used as a soldering medium, and some 



344 DOMESTIC SCIENCE. 

of this poisonous substance occasionally becomes 
mixed with the contents of the can. 

Drying", an effectual method of preservation, ad- 
mits of application to meats, vegetables, and fruits. 
Appearance indicates, and analysis proves, that food- 
stuffs in their natural condition all contain a large 
proportion of water. The bacteria of putrefaction 
cannot thrive unless freely supplied with water; dry- 
ness renders them inert, and is an effectual hindrance 
to their destructive growth. Succulent vegetables and 
fruits by drying lose many of their flavoring in- 
gredients, though but little real nutriment is sacrificed. 
To be prepared for the table, dried foods should be 
soaked in water, that they may absorb the proportion 
of liquid formerly lost. 

Chemical Antiseptics are also used. But for the 
very small quantities of antiseptic chemicals necessary 
to produce the desired effect, great danger would attend 
their use, for none of them are of themselves con- 
ducive to health. 

Common Salt is one of the most efficient among 
these. If dry salt be added to fresh meat, a brine 
soon forms ; this is due to the strong attraction which 
salt possesses for water, whereby it robs the meat of 
its juices ; the meat in itself becomes in reality dryer, 
though outwardly it appears in the very opposite con- 
dition. That salted meat does not putrefy is due 
mainly to the abstraction of water : though salt itself 
in large quantities is fatal to bacterial existence. Much 
of the mineral matter of the meat is dissolved with 
the juices in the brine during the salting process ; and 



PRESERVATION OF FOOD STUFFS. 345 

meat so preserved is consequently deficient in these 
essentials. The eating of salted flesh, if long con- 
tinued, may produce serious derangement of health. 
Scurvy is a common disease among sailors who are 
fed on such meat. 

Sugar is also a valuable antiseptic ; it is used in 
pickling and curing meats, but more especially in the 
preserving of fruits. By dissolving in the fruit juices, 
and thus converting them into syrups, sugar exercises 
a drying effect upon the tissues, and so retards de- 
composition ; and farther, the mere presence of sugar 
in abundance prevents the growth of bacteria. In 
dilute syrups, fermentation may be set up, unless the 
containing vessels are secured by hermetic sealing 
against the possible entrance of germ-laden air, as is 
done in the case of bottled and canned fruits. 

Alcohol preserves organic tissues immersed in it, 
by uniting with the constituent water, and thus dry- 
ing the solid parts. A little strong alcohol poured 
upon the white of an egg converts the albumen into a 
tough, leathery mass, which analysis shows to be very 
deficient in water as compared with the liquid white ; 
and by the process the alcohol is correspondingly 
diluted. Alcohol exerts a destructive effect upon 
bacterial organisms that may find entrance to it, and 
thus it tends to prevent putrefactive changes. 

Vi7iegar checks decomposition of organic matter. 
Its general properties and uses have been already 
dwelt upon. Fish and meats are sometimes pre- 
served in oil. This medium prevents the access of air 
to the immersed, substances, and thus effectually 



346 DOMESTIC SCIENCE, 

guards against the entrance of germs of decomposi- 
tion. 

Creosote is a powerful antiseptic ; a very weak 
solution of the substance, if poured upon meat, will 
prevent decomposition of the latter even in the hottest 
weather. Creosote is the chief of the irritating con- 
stituents of smoke, and the efficacy of smoke-drying 
as a means of preservation is mostly due to the influ- 
ence of this substance. The amount of creosote nec- 
essary for preservation is extremely small, else great 
danger would attend its use, for the substance is a 
strong poison. 

Various preparations of horic acid sly e now used as 
antiseptics ; principally for preserving meats. The 
acid is introduced into the circulatory system of ani- 
mals before death so that the flowing blood may dis- 
tribute the material throughout the body.* The 
so-called "glacialine," now sold in packages and 
warranted to be a safe preservative, consists mainly of 

*Mattieu Williams thus describes the process and illustrates its 
efficacy: "The animal is rendered insensible, either by a stun- 
ning blow, or by an antesthetic, with the heart still beating. A 
vein, usually the jugular, is opened, and a !?mall quantity of blood 
let out. Then a corresponding quantity of a solution of boric 
acid raised to blood heat is made to flow into the vein from a ves- 
sel raised to a suitable height above it. The action of the heart 
carries this through all the capillary vessels into every part of 
the body of the animal. * * * After the completion of 
this inoculation, the animal is bled to death in the usual manner. 
From three to four ounces of boric acid is sufficient for a sheep of 
average weight, and much of tliis comes away with the final 
bleeding. On April 2nd, 1884, 1 made a hearty meal on the roasted 
boiled and stewed flesh of a sheep that was killed on February 
8th, the carcass being in the meantime in the basement of the 
Society of Art<. It was perfectly fresh, and without any percepti- 
ble flavor of the boric acid ; very tender and full flavored as freah. 
meat." 



PRKSEKVATIOX OF FOOD STUFFS. 347 

borax. A small amount of borax added to milk 
hinders fermentation and thus prevents for a time the 
souring of the liquid. 

SuUcylic acid is growing in favor as a preservative 
of fruits and vegetables. The use of this has been 
proved by experience to be detrimental. The substance 
is a potent medicine, and when used continuously or 
in large quantity it is a poison. Many of the preserv- 
ative powders and solutions now offered for sale con- 
sist mainly of salicylic acid, and should be avoided. 

Preservation of Eg'gS. — Eggs may be preserved 
by varnishing the porous shells, so as to prevent the 
entrance of air. By coating the exterior with an 
impervious layer, the natural appearance of the inner 
parts may be preserved. This may be effected by 
dipping the eggs in a prepared solution of gum, or in 
melted fat or paraffine. They should then be carefully 
packed. Dr. Youmans kept eggs in good condition 
for upwards of a year, by packing them in salt, small 
ends downward ; after that time they had lost nearly 
half their weight, but had not putrefied ; the interior 
of the Q^g, however, had become thick and shrunken. 
Among recent methods, that of subjecting eggs to the 
action of sulphur dioxide, produced by the burning of 
sulphur, has produced good results. 



REVIE\Ar. 

1. Show the great liability of food stuffs' to undergo decay. 

2. Define "putrefaction," and "fermentation." 

3. What does the microscope teach us as to the nature of 
such decomposition processes? 



348 DOMESTIC SCIENCE. 

4. Explain the effect of freezing in preventing decay. 

5. Illustrate the practical use of this mode of preservation. 

6. Explain the effect of hermetic sealing in preventing 
decay. 

7. Explain why pure thoroughly filtered air will not induce 
decay in perishable articles. 

8. What practical application may be made in preserving 
fruit ? 

9. Describe the process of canning fruits, vegetables and the 
like. 

10. What dangers attend the use of canned goods ? 

11. Explain the effect of drying in preserving foods. 

12. What is a chemical antiseptic ? 

13. Name the principal chemical antiseptics. 

14. Explain the preserving effect of salt. 

15. Of sugar. 

16. Of alcohol. 

17. Of oil. 

18. Of creosote. 

19. Of boric acid. 

20. Of salicylic acid. 



PART IV. 

CLEANSING AGENTS ; AND POISONS AND 
THEIR ANTIDOTES. 



CLEANSING AGENTS. 351 



CHAPTEU 36. 

CLEANSING AGENTS. 

Water as a Cleansing" Agent. — The great sol- 
vent power possessed by water renders that liquid par- 
ticularly useful as a cleansing medium, and the need 
of such a substance must be apparent to all. The 
furniture of the house, the utensils of the cook-room, 
the clothing of the body, and especially the skin itself, 
all call for periodical washings. Though water has ap- 
propriately been termed the "universal solvent," it pos- 
sesses widely varying dissolving powers for different 
substances ; thus, a pinch of sugar or of salt will dissolve 
readily in a goblet of water, whereas a like quantity 
of sand may remain apparently undissolved for an in- 
definite time, and for oily matters water exhibits pos- 
itive repulsion. Yet very delicate chemical analysis 
shows that some portion even of sand and of oil may 
be dissolved by water. As a rule, the solvent power 
of water is favored by heat ; the use of hot water 
for laundry and house cleansing is therefore indicated. 

Alkalies as Cleansing Agents. — A greatly in - 

creased solvent effect is produced by adding to the water 
certain chemical substances, prominent among which are 
the alkalies, potash, soda, and ammonia. From very 
early times, people have been in the habit of using 
wood ashes as an aid in washing clothes : the effective 
ingredient of the ashes being potassium carbonate 



352 DOMESTIC SCIENCE. 

(commonly called "potash," because prepared from 
the ashes of fires used in heating the cooking pots). 
A strong solution of potash, or of either of the other 
alkalies named, possesses strongly corrosive powers ; 
only very dilute solutions can therefore be used for 
ordinary cleansing purposes, lest while removing the 
impurities the fabrics and objects themselves be in- 
jured. 

Soaps. — Experience has taught that it is better to 
restrain the corroding ardor of the alkalies by first 
combining them with fats so as to form soaps. Ordi- 
nary fats and fixed oils consist each of two main 
ingredients, viz., glycerine and an acid, the latter 
commonly called a fatty acid. When heated with 
strong alkalies, fats readily decompose, liberating their 
glycerine, while the fatty acids unite with the alkalies 
to form salts. Thus, fats containing olein, if heated 
with soda, would form glycerine and sodium oleate ; 
palmitin and stearin, the other two common fats, if 
similarly treated, would form sodium palmitate and 
sodium stearate ; if potash were used as the alkali, 
potassium oleate, palmitate, or stearate would be 
formed. These compounds of alkalies and fatty acids 
are soaps. Most soaps dissolve in water, producing 
very viscid solutions, which when agitated readily en- 
tangle air, producing lathers. When used with hard 
waters, the alkali in the soap is exchanged for the 
lime or magnesia of the water, and thus soaps of lime 
or magnesia are formed ; these are insoluble in water, 
and rise to the surface as scum. 

Soap-making". — The chemical process of forming 



CLEANSING AGENTS. 353 

soap by decomposing fats through the agency of alka- 
lies, is known as saponification ; it may be watched 
and studied at any soap- boiling establishment. The 
alkalies used in soap making are usually the hydrates 
of the metals; these, from their great corrosive 
powers, are called caustic alkalies. The soap in form- 
ing dissolves in the water present ; as the boiling con- 
tinues much of the water is evaporated, the soap then 
separates from solution and rises to the surface ; this 
is removed, shaped in molds, and allowed to partially 
dry before it is used. If caustic soda be used as the 
saponifying alkali, the soap may be more advan- 
tageously separated by adding common salt to the 
soap solution, whereby a strong brine is formed, 
which coagulates the soap and causes its ready separa- 
tion from the water. This "salting out" is not prac- 
ticable in the making of potash soaps, because the salt 
would decompose the potassium compound, forming a 
soda soap. 

Soaps— Hard and Soft.— There is great differ- 
ence between the soaps made from these two common 
alkalies. Caustic potash is highly deliquescent ; that 
is to say, it possesses a great thirst for water, and so 
keeps the soaps formed by it in a partially liquid state ; 
from such soaps the glycerine cannot be well separ- 
ated, this adds to the softness of the soap. Potash 
soaps are always soft soaps ; soda on the other hand 
forms hard soaps. The consistency of the soap de- 
pends in some degree upon the fats used, though this 
condition is mostly influenced by the alkali ; thus, hard 
tallow will produce a firmer soap than will olive oil ; 



354 DOMESTIC SCIENCE. 

yet an oil with soda will saponify to a comparatively 
hard soap, while solid tallow with potash will produce 
a semi -liquid soap. 

Fats Used in Soap Making. — Among the com- 
mon fatty bodies used in the preparation of soap may 
be named tallow, lard, palm oil, olive oil, cotton- 
seed oil, cocoa-nut oil, for hard soaps ; and fish oil, 
linseed oil, and marrow for soft soaps. Certain fine 
grade toilet soaps are made of almond oil and sperma- 
ceti. Cocoa-nut oil is peculiar among fats, it being 
unaffected by weak alkalies, but readily saponifiable 
by strong alkalies ; the resulting soap is soluble in 
brine, and, consequently, cannot be separated from water 
in the course of manufacture by " salting out." The 
oil is heated to a low temperature only, the lye is 
then stirred in, and saponification takes place at once. 
Cocoa-nut oil soap lathers with salt water; it is 
therefore valuable for use at sea, and is known as 
marine soap. 

Colored Soaps. — Common yellow soaps contain 
resin ; other tints are usually produced by special 
coloring matters. The mottled appearance of some 
soaps is due to the presence of insoluble me- 
tallic oxides, which are stirred into the soap as it 
hardens. Transparent soaps are produced by dissolv- 
ing good hard soap in alcohol, then evaporating the 
solution till a clear jelly is obtained ; such soaps are 
usually pure and good, though they waste rapidly and 
are costly. True Castile soap is made from olive oil 
and soda ; the color is due to metallic oxides stirred 
into the mass. Many imitations of Castile soap are 



CLEANSING AGENTS. 355 

now made from common fats. Glycerine soaps con- 
sist of a mixture of hard soap and glycerine ; the 
latter substance in small quantity only ; an excess of 
glycerine causes the soap to soften and gives but weak 
lathering properties, whereas a small amount of 
glycerine renders the lather tenacious and persistent. 

Impure Soaps. — The poorer grades of soaps are 
sometimes made from very impure fats ; in such the 
microscope has revealed the presence of bits of bone, 
half -decayed areolar tissue, and even pus cells; very 
serious results may follow the use of soaps of this 
sort, from the poisonous matter being absorbed 
through the skin. Such foul accompaniments, how- 
ever, are comparatively rare ; the chief inconvenience 
attending the use of poorly made soaps lies in the 
excess of free alkali which they contain. The smarting 
sensation following the use of such soaps on the skin 
is caused by the solvent action of the free alkali ; 
relief may be found through the application of some 
verp dilute acid, such as vinegar, or lemon juice. 

Adulterated Soaps. — Many soaps are largely 
adulterated, though most of the additions are com- 
paratively harmless. The commonest adulterants are 
fuller's earth, starch, and soluble silicates. Sodium 
silicate enables soap with which it is mixed to absorb 
a large quantity of water, and so greatly increases the 
weight; though, as the substance itself is a harmless 
detergent, the ill effects of its introduction are some- 
what modified. 

Washing" Compounds. — With some soaps a 

quantity of fine sand or other hard insoluble powder 



356 DOMESTIC SCIENCE. 

is incorporated ; this by its abraiding action aids the 
cleansing operations. Most washing compounds are 
partially dried and finely divided soaps ; all such 
substances, as also common "washing powder," 
contain a great excess of alkali. "Washing fluids'' 
are mere solutions of the caustic alkalies, soda and 
potash ; such are of advantage where very hard waters 
are used, though such excess of alkali is generally 
ini'urious to the skin, as also to most fabrics submitted 
to its action. When soap dissolves in water, some 
of its alkali is set free ; this combines in the washing 
process with the oily matters of the dirt, and by 
saponifying such renders them miscible in water. 

Ammonia.^ — Besides soap, and the free alkalies, 
potash and soda, which are the commonest cleansing 
agents, aqua ammonia is also largely employed. This 
should be used only when greatly diluted with water. 
With oily matter it forms a soapy fluid, which is 
soluble in water; hence the value of ammonia for 
removing grease from cloth, etc. Water containing a 
tablespoonful of ammonia to the gallon is an excel- 
lent wash for woodwork, and such a mixture is fre- 
quently applied to carpets for the purpose of brighten- 
ing their colors. 

Other Solvents for Fats. — Besides ammonia, 
already mentioned, spirits of turpentine, camphene 
(rectified turpentine), and benzine (gasoline), are 
also efficient solvents for most fixed oils ; they are 
therefore useful in removing grease from clothing. 



CLEANSING AGENTS. 357 

REVIEW. 

1. Show the value of water as a cleansing agent. 

2. By what means may the solvent powers of water be in- 
creased. 

3. What is soap ? 

4. Describe the general method of making soap. 

5. Explain the cleansing action of soap. 

6. What is the scum formed by soap when acted upon by 
hard water ? 

7. Explain the process of saponification. 

8. Explain the difference between hard and soft soaps. 

9. Name the principal fats used in making soaps. 

10. What do you know of Castile soap ? 

11. Of glycerine soaps ? 

12. Show the dangers of using soap made of impure fats. 

13. What do you know of the composition and action of 
washing powders ? 

14. Explain the cleansing action of ammonia. 

15. Name the common cleansing agents with which you are 
acquainted. 



358 DOMESTIC SCIENCE. 



CHAPTER 37. 

BLEACHING. 

Sun-Bleaching". — it is often found desirable to 
modify or to remove the natural colors of textile 
goods ; the process of whitening such fabrics is known 
as bleaching.* It has long been an art among men, 
they having learned its fundamental principles from 
observing certain operations in Nature. Light and air 
are universal bleaching agents. 

The earliest processes of artificial bleaching consisted 
in exposing the colored fabrics to light and air. This 
was accomplished by spreading the goods on grass 
plats in the open sunshine, and by occasionally wetting 
them if dews or rain did not afford sufficient moisture. 
The explanation of the whitening process so con- 
ducted is simple as far as w^e understand it; the 
oxygen of the air unites with the organic compounds 
constituting the coloring matters, thus changing their 
composition with consequent loss of their property of 
color. This operation is most applicable to cottons and 
linens. Under the best conditions sun -bleaching is a 
slow process ; in Holland where the art was most 
highly developed, the bleaching required for its com- 
pletion eight or nine months ; and oftentimes if the 

* The old Knglisli name for bleachers is " whitesters," or "whit- 
sters;" it fully expresses the nature of their occupation. 



BLKACHING. 359 

season were cold and wet the fabrics were injured by 
the continual exposure. The Dutch mode of pro- 
cedure in bleaching, consisted of treating the cloth for 
a week with caustic alkali or lye; then came an im- 
mersion in buttermilk, and then the many months' 
exposure to sunlight and dew. The large space needed 
for the process gave to bleaching establishments the 
common name of " bleach -fields." 

Chemists have discovered several substances that 
possess strong bleaching powers. Of these, chlorine 
and sulphur dioxide are among the chief; and they are 
the ones that are best adapted for domestic applica- 
tion. 

Chlopine as a Bleaching' Ag'ent.— Chlorine is a 

gas, yellowish green in color, and of penetrating, 
strongly suffocating odor. It is possessed of remark- 
ably strong chemical affinity for other elements, and 
will often decompose other compounds to form with 
the elements combinations of its own. Upon this 
property depends the value of chlorine as a bleaching 
agent, and, as will subsequently be seen, its efficacy as 
a disinfectant also. The tinted petal of a flower, a 
green leaf, or a piece of cloth dyed with vegetable 
colors, may be readily whitened by exposure to the 
gas. To demonstrate, place in a wide -mouth bottle a 
little chloride of lime; — this substance is a convenient 
source of chlorine, and is commonly known as 
"bleaching powder;" pour upon it a little dilute 
acid, — muriatic acid is best; — then quickly cover the 
mouth of the jar with a plate of glass. The vessel 
will soon become filled with the green gas, — chlorine ; 



560 DOMESTIC SCiENCfi. 

if you desire to test its odor, do so cautiously, for if 
inhaled in quantity it produces painful and injurious 
spasms. Suspend in the upper part of the vessel some 
bits of colored calico, and a colored flower, — all of 
which must be moistened ; the colors disappear with 
magical quickness. 

Another pretty demonstration of the decolorizing 
action of chlorine consists in conducting the gas or 
pouring chlorine water into red ink, colored wine, in- 
fusion of red cabbage, or of indigo ; the tints almost 
instantly disappear. Printers' black ink is not so 
affected ; as its color is due to finely divided carbon 
(lampblack), which is not eager to form combinations 
with other elements. Dry substances are not whitened 
by chlorine, and this fact is a key to an understanding 
of the bleaching process. Chlorine possesses a strong 
affinity for hydrogen, so strong indeed as to readily 
take the hydrogen from water, thus leaving the oxygen 
free ; this oxygen in its nascent or freshly liberated 
state eagerly unites with the organic coloring com- 
pounds, and, as was explained in the case of sun- 
bleaching, robs them of color. So that chlorine is 
not the true bleacher after all. Oxygen is the efficient 
color destroyer, the chlorine simply liberates the oxy- 
gen from its combination in water. Thus there is 
great similarity between the processes of sun -bleach- 
ing and "chlorine- bleaching :" each is a result of oxi- 
dation. 

The bleaching operation may be carried too far ; for 
if after the coloring matters have been acted upon 
chlorine be still allowed to decompose the water con- 



BLEACHING. 361 

tained within the pores of the cloth, the energetic 
oxygen will attack the textile fibers themselves, and 
this will rot the fabrics. Exposure to gaseous chlorine 
is very apt to partially destroy the fabrics ; a more 
practical method, and the one most commonly adopted, 
consists in immersing the goods to be bleached in a 
solution of chloride of lime ; they should be kept in 
the bath several hours, — sometimes days are required ; 
they are then to be removed, and if the whitening be 
not satisfactory they should be placed in a tub of 
acidified water ; the acid will liberate chlorine in quan- 
tity from the bleaching powder within the pores ; the 
acid treatment must be carefully watched, lest it result 
injuriously to the goods.* 

Sulphur Dioxide in Bleaching". — Colors bleached 

through the agency of chlorine cannot be restored, the 
pigment having been destroyed. Chlorine- bleaching is 
not applicable to straw, wool or silk. For these, sulphur 
dioxide is employed as a whitener. This gas may be 
produced by burning sulphur in air ; it is colorless, 
and produces an intensely irritating effect within the 

* " A very elegant application of chlorine to bleaching purposes 
is made in the printing of bandanna handkerchiefs. The white 
spots which constitute their peculiarity are thus produced. First 
of all, the whole fabric is dyed of one uniform tint, and dried. 
Afterwards, many layers of these handkerchiefs are pressed to- 
gether between lead plates, perforated with holes conformable to 
the pattern which is desired to appear. Chlorine solution is now 
poured upon the upper plate, and finds access to the interior 
through the perforations. By reason of the great pressure upon 
the mass, the solution cannot, however, extend laterally further 
than the limits of the aperture?, whence it follows that the 
bleaching agent is localized to the desired extent, and figures 
corresponding in shape and size to the perforations are bleached 
white upon the dark ground." Faraday. 

12 



362 DOMESTIC SCIENCE. 

respiratory passages. Like chlorine, it is soluble in 
water, and its solution possesses the essential proper- 
ties of the gas. Its bleaching powers may be prettily 
illustrated by holding a moist red rose over a bit of 
burning sulphur ; a lighted match held beneath the 
flower is often effective. The process of sulphur - 
bleaching is conducted by moistening the articles and 
suspending them in closed chambers in which sulphur 
is being burned. A large box or an inverted tub may 
be used as a bleaching chamber. The moistening of 
the goods is to aid the absorption of the gas. The col- 
oring matters so bleached are not in reality destroyed ; 
the union between them and sulphur dioxide is an 
unstable one, and the colors are after a time restored 
in part. Flannels that have been bleached with sul- 
phur dioxide often regain their color when washed 
with alkaline soaps. Certain chemicals — e. g. sul- 
phuric acid, will promptly restore the color to articles 
so bleached. To illustrate this, prepare an infusion of 
logwood ; conduct into it gaseous sulphur dioxide, or 
pour into it an aqueous solution of the gas ; the color 
immediately disappears ; now add a little sulphuric 
acid ; the color is as promptly restored. Sulphur- 
bleaching is therefore only practiced in cases to which 
chlorine is not applicable, as in whitening silk, wool, 
and straw. 



REVIEW. 

1. What is bleaching? 

2. Describe the earliest known processes of bleaching. 

3. Name the commonest chemical bleaching agents. 



BLEACHING. 363 

4. Describe a demonstration of the bleaching action of 
chlorine. 

5. How may chlorine be prepared for experimental work? 

6. Explain the chemical changes occurring in chlorine 
bleaching. 

7. Name a common and an easily employed source of chlorine. 

8. Describe the method of using chloride of lime in bleaching. 

9. Explain the methods of printing bandanna handkerchiefs. 

10. For what materials is chlorine not adapted as a bleach- 
ing agent? 

11. Describe a method of preparing sulphur dioxide. 

12. State some of the properties of sulphur dioxide. 

13. Explain the instability of the whitening resulting from 
sulphur dioxide bleaching. 



364 DOMESTIC SCIENCE. 



CHAPTER 38. 

DISINFECTANTS. 

Disinfectants and Deodorizeps.— Certain kinds 

of impurity cannot be removed from our dwellings by 
the ordinary methods of cleansing. The presence of 
dust in the house has been shown to be universal ; 
the complex nature of the dust, consisting as it does 
of inorganic and organic matters, and even of living 
organisms, has been dwelt upon; the close relation- 
ship between the progress of contagious diseases 
within the body and putrefaction without is now 
well understood. Following a consideration of these 
facts, the operation of disinfectants will be clear. 

A disinfectant is a substance that destroys the 
effluvia of putrefaction, and the poison of contagion; 
yet the term, by a popular inaccuracy, is applied also 
to absorbents and deodorizers. Foul smells are 
usually associated with poisonous properties; the dis- 
agreeable odor seems to be a danger signal, affixed in 
wisdom to many noxious matters. Fatalities from 
inhalation of the toxic coal gas, the nauseating hydro- 
gen sulphide, and the deadly prussic acid would be 
more frequent but for their disgusting odors. Sub- 
stances that absorb ill-smelling matters, therefore, may 
be of value, yet they hold the offensive gases much as 
a sponge retains water, and they may again allow the 
escape of the foul matter. 



DISINFECTANTS. 365 

Certain odorous substances are wrongly termed 
deodorizers, such as cascarilla, cologne, and other 
extracted perfumes, musk, fragrant spices, aromatic 
mixtures, burning coffee, and even smoldering paper 
and rags ; these, however, merely hide the bad odor 
by substituting a stronger one. Such substances are 
almost valueless as disinfectants.* 

Charcoal and Lime are efficient absorbents of 
many foul gases. A solution of hydrogen sulphide 
shaken with fresh charcoal loses almost immediately 
its foul odor. Lime is less efficacious, yet it is valu- 
able. The practice of whitewashing the walls of 
rooms, and especially of cellars and such places is 
very beneficial in sweetening the inclosed atmosphere ; 
though, as the lime soon loses this power, frequent 
renewal of the wall -wash is necessary. 

The merits of charcoal as an absorbent of gases are 
not generally recognized. It is used in water filters 
to arrest gaseous impurities ; organic filth of many 
kinds, even the bodies of dead animals, if covered with 
a layer of freshly heated charcoal may undergo decom- 
position with no escape of foul effluvia ; tainted meat 
packed in charcoal loses its disagreeable smell ; and the 
air of sick rooms may be greatly improved by placing 

* " They (perfumes) are the only resources in rude and dirty 
times, against the offensive emanations from decaying animal 
and vegetable substances, from undrained and untidy dwellings, 
from unclean clothes, from ill-washed skins, and ill-used 
stomachs. The scented handkerchief in these cases takes the place 
of the sponge and the shower bath; the pastile hides the want of 
ventilation, the attar of roses seems to render the scavenger un- 
necessary, and a sprinkling of musk sets all other stenches and 
smells at defiance." (Quoted.) 



366 DOMESTIC SCIENCE. 

therein charcoal in shallow pans. Finely divided char- 
coal is one of the most efficient and least harmful of 
powders for the teeth ; being soft it produces no in- 
jurious abrasions of the enamel, while its deodorizing 
action does much to sweeten the mouth.* A small 
amount of pure charcoal swallowed immediately after 
onions will keep the breath free from disagreeable 
effluvia. A lump of clean charcoal in a cooking vessel 
with cabbage, onions, or other strong- smelling vege- 
tables, will prevent the escape of disagreeable odors. 
Roasted coffee is partially charred vegetable matter ; a 
few coffee seeds may be substituted for the lump of 
charcoal in the cooking process just named. Bone 
black or animal charcoal has great affinity for the 
elements of vegetable colors, and is of great use as a 
decolorizer of syrups, etc., which are filtered through 
it. 

Chlopine as a Disinfectant. — Chlorine, in its 

pure state is a pale yellowish -green gas; intensely 
irritating if inhaled. Its chief properties have been 
considered in connection with its use as a bleaching 
agent (page 359). Hydrogen sulphide, ammonia, and 
most other compounds formed by the putrefaction of 
organic matter are decomposed by the gas. If allowed 
to escape in closed rooms it will destroy or render 
inert most foul matters ; but it is likely to bleach the 

* Charcoal from wood is apt to be "gritty," such may be of 
injury if rubbed on the teeth. The best kind for the purpose 
named may be made by charring the crust Of bread. Let the 
bottom crust of a loaf be removed in one piece, and this be com- 
pletely charred before or over a glowing fire. It is then to be 
finely pulverized. 



DISINFECTANTS . 367 

colors of furniture and drapery in the presence of 
moisture, and to corrode metals. Its most accessible 
source is chloride of lime, or bleaching powder, which 
is prepared by saturating slaked lime with the gas. 
The powder contains about 30 per cent, available 
chlorine, which is set free very slowly by mere ex- 
posure ; but may be liberated very rapidly by the ad- 
dition of an acid. The common attempt at disinfection 
by simply scattering lime chloride about the premises 
is a very ineffectual one ; the substance should be 
mixed with acid — hydrochloric acid, sulphuric acid, or 
even strong vinegar may be used. For disinfecting 
rooms, chlorine may be liberated by mixing 4 ounces 
of hydrochloric (muriatic) acid, previously diluted 
with three times its volume of water, and 1 pound of 
chloride of lime. Let the mixture be made in an 
earthen vessel ; the room should be immediately 
closed, and be kept unopened for 24 hours. Another 
method of chlorine preparation consists in treating 
manganese dioxide (two parts by weight) with strong 
hydrochloric acid (three parts by weight). 

Sulphur Dioxide as Disinfectant. — Sulphur 

dioxide is a colorless gas, entirely irrespirable. It 
may be easily prepared by burning sulphur, and is an 
efficient disinfectant. It is in most respects best 
adapted among disinfectants for general use. Wet 
fabrics containing vegetable dyes are bleached, how- 
ever. To prepare and use the gas :* set an iron pan 

*The " sulphur candles " now offered for sale by druggists afford 
a convenient method of disinfecting by sulphur on a small scale; 
but being somewhat more expensive the method is not likely to 
displace the simple sulphur burning for large buildings. The 



368 DOMESTIC SCIENCE. 

on bricks in the middle of the floor ; as an additional 
precaution the bricks may be placed in a shallow tub 
containing water ; put the sulphur (roll brimstone is 
best adapted) in the pans, allowing at least two pounds 
for a room 10 feet square; light by adding a small 
shovelful of glowing coals, or by pouring a table - 
spoonful of alcohol over the brimstone and applying a 
match. Let the room be closed, and remain so for 
24 hours. Do not use chlorine and sulphur dioxide 
together ; they partially neutralize each other. 

Carbolic Acid is prepared from coal tar ; it is a 
colorless crystalline solid, though by exposure to light 
and air it soon darkens, and if at all diluted it becomes 
liquid. In an unmixed state it is very corrosive to 
organic substances, but being soluble in water it may 
be diluted to any degree. It is a sure destroyer of 
bacterial life if brought in contact with the organisms, 
and is also an antiseptic, acting in this respect much 
like creosote. A two per cent, solution of carbolic 
acid ; i. e. 2 parts acid diluted with 98 parts water, is 
suitable for most purposes of disinfection. The odor 
of the acid is objectionable to many persons ; this may 
be somewhat modified by dissolving camphor in the 
acid before dilution. Many prepared disinfectants now 
offered for sale are mixtures of carbolic acid and 



sulphur candle consists of a quantity of sulphur which has been 
poured while molten into a shallow dish of sheet iron. The sul- 
phur mass is penetrated by porous wicks, previously prepared by 
soaking in a solution of nitre, so that they burn readily much as 
fuses do. After preparing the room, all that is necessary in using 
such a candle is to set it in a wash-bowl or other convenient vessel 
containing a little water, and light the wicks. 



DISINFECTANTS. 369 

dilutents. Carbolic powders consist of the acid mixed 
with sawdust, lime, or clay. 

Thymol is another product of coal tar distillation. 
Its odor is agreeable, and as its disinfecting action is 
similar to that of carbolic acid, it is largely used as a 
substitute for the latter. It may be purchased in the 
solid state, or as spirits of thymol, consisting of 1 part 
thymol dissolved in .3 parts alcohol of 85 per cent, 
strength. To prepare for use, add one table -spoonful 
spirits of thymol to a half gallon of water. This solu- 
tion may be sprinkled about the apartment, even on 
carpets and draperies without serious detriment ; still 
further diluted, it may also be applied to the flesh as a 
wash, after exposure to contagion. Do not allow it to 
enter the eyes. 

Feppous Sulphate, op Gpeen Vitpiol, also 

called copperas, may be used as a disinfectant ; it is 
cheap. It exists as pale green crystals, and is very 
poisonous. Ferrous sulphate is a good disinfectant ; 
for use it should be dissolved in water, — 2 pounds of 
the crystals to a gallon of water. This solution may 
be improved by the addition of 2 ounces carbolic acid 
per gallon of fluid. AVhen required in large quantity, 
a basket containing fifty or sixty pounds of the 
crystals may be suspended in a barrel of water ; the 
solution soon becomes saturated. 

Lime and ChaPCOal, though absorbents rather 
than disinfectants, occur as ingredients of many 
patented disinfectant preparations. Gypsum (lime 
sulphate) is mixed with carbolic acid, and used for 
disinfecting stables, etc. 



370 DOMESTIC SCIENCE. 

Corrosive Sublimate, called also mercuric 
chloride, is a powerful disinfectant, and acts by de- 
stroying the germs of decay. It readily coagulates 
albuminous matters. One part of the substance in 
1000 parts of water forms a solution of sufficient 
strength to kill most bacteria. It is a deadly poison, 
and does not admit of general use. It should be 
employed only under skilled direction. 

Zinc Salts as Disinfectants. — Certain salts of 

zinc, especially the sulphate (white vitriol), and the 
chloride (butter of zinc), are good disinfectants. 
With albuminous matters they form insoluble com- 
pounds, and act as absorbents for certain gases. The 
substances are poisonous and must be used with care. 
A very good zinc disinfectant consists of zinc sulphate, 
1 pound ; common salt, y^, pound ; and water, 4 
gallons. Infected clothing, bedding, and the like 
may be immersed and boiled in the solution. 

Lead Chloride is of service as a disinfectant, but 
must be used with care because of its poisonous 
nature. To prepare : Dissolve 1 drachm of lead 
nitrate in a quart of boiling water ; dissolve also 4 
drachms of common salt in a bucket of water, and 
mix the solutions. A copious precipitate of lead 
chloride will form, much of which will settle ; the 
supernatant fluid is ready for use. It may be 
sprinkled about the floor, or in drains and gutters. 

Heat, Air, and Light as Disinfectants. — 

Heat is an important agent of disinfection. Clothing, 
carpets, and such articles as admit of this treatment, 
should be boiled in water, or subjected to a dry heat 



DISINFECTANTS . 371 

in an oven at 250° to 300° F., for several hours. 
Woolen fabrics are injured by this treatment. 

Air and Lig'ht. — For house disinfection, abund- 
ance of fresh air, free access of light, and strict 
cleanliness are among the most valuable of disinfect- 
ants. No chemical preparation can take the place of 
the natural purifiers, air and light, and no cure of 
uncleanliness is equal to the prevention of such a 
state. 

Below is given a brief code of instructions for the 

Manag-ement of Contag'ious Diseases, as author- 
ized by the National Board of Health :* 

INSTRUCTIONS FOR DISINFECTION. 

Disinfection is the destruction of the poisons of 
infectious and contagious diseases. 

Deodorizers, or substances which destroy smells, 
are not necessarily disinfectants, and disinfectants do 
not necessarily have an odor. 

Disinfection cannot compensate for want of cleanli- 
ness nor of ventilation. 

I, Disinfectants to he employed. 

1. Roll sulphur (brimstone) for fumigation. 

2. Sulphate of iron (copperas) dissolved in water, 
in the proportion of one and a half pounds to the 
gallon, for soil, sewers, etc. 

3. Sulphate of zinc and common salt dissolved to- 
gether in water, in the proportion of four ounces 

* These instructions were prepared by a special committee of 
eminent scientific men. They are here quoted from Dr. Tracy's 
admirable little " Hand Book of Sanitary Information." 



372 DOMESTIC SCIENCE. 

sulphate and two ounces salt to the gallon, for cloth- 
ing, bed linen, etc. 

II. — How to use disinfectants. 

1. In the sick room : The most available agents are 
fresh air and cleanliness. The clothing, towels, bed- 
linen, etc., should, on removal from the patient, and 
before they are taken from the room, be placed in a 
pail or tub of the zinc solution, boiling if possible. 
All discharges should either be received in vessels 
containing copperas solution, or when this is imprac- 
ticable, should be immediately covered with copperas 
solution. All vessels used about the patient should be 
cleansed with the same solution. Unnecessary furni- 
ture, especially that which is stuffed, carpets and 
hangings, should when possible be removed from the 
room at the onset, otherwise they should remain for 
subsequent fumigation and treatment. 

2. Fumigation with sulphur is the only practicable 
method for disinfecting the house. For this purpose 
the rooms to be disinfected must be vacated. Heavy 
clothing, blankets, bedding, and other articles which 
cannot be treated with zinc solution, should be opened 
and exposed during fumigation as directed below. 

3. Premises: Cellars, yards, stables, gutters, 
privies, cess-pools, water-closets, drains, sewers, etc., 
should be frequently and liberally treated with copperas 
solution. 

4. Body and bed-clothing, etc. It is best to burn 
all articles which have been in contact with persons 
sick with contagious or infectious diseases. Articles 



DISINFECTANTS. 373 

too valuable to be destroyed should be treated as 
follows: (a) Cotton, linen, flannels, blankets, etc., 
should be treated with boiling-hot zinc solution, intro- 
duced piece by piece : secure thorough wetting, and 
boil for at least half an hour. (b) Heavy woolen 
clothing, silks, furs, stuffed bed -covers, beds, and 
other articles which cannot be treated with the zinc 
solution, should be hung in the room during fumiga- 
tion, their surfaces thoroughly exposed, and pockets 
turned inside out. Afterward they should be hung 
in the open air, beaten and shaken. Pillows, beds, 
stuffed mattresses, upholstered furniture, etc., should 
be cut open, the contents spread out and thoroughly 
fumigated. Carpets are best fumigated on the floor, 
but should afterwards be removed to the open air and 
thoroughly beaten. 

Corpses, especially of persons that have died of any 
infectious or malignant disease, should be thoroughly 
washed with a zinc solution of double strength; should 
then be wrapped in a sheet wet with the zinc solution, 
and buried at once. 



REVIEW. 

1. What is a disinfectant? 

2. Show the difference between true disinfectants an^ 
absorbents. 

3. Between true disinfectants and deodorizers. 

4. Show the value of charcoal as an absorbent. 

5. What do you know of lime as an absorbent ? 

6. Explain the disinfecting action of chlorine. 

7. How would you use chloride of lime as a disinfectant? 

8. What do you know of sulphur- dioxide as a disinfectant? 



374 DOMESTIC SCIENCE. 

9. How would you prepare and use sulphur dioxide in dis- 
infecting? 

10. What do you know of carbolic acid as a disinfectant? 

11. How would you use it? 

12. State what you know of the disinfecting value of thymol. 

13. How would you use the substance? 

14. For what special uses in disinfecting is iron sulphate 
adapted? 

15. How should the substance be used? 

16. What do you know of corrosive sublimate as a disinfectant? 

17. Explain the use of zinc salts as disinfectants. 

18. State the uses of lead cbioriie as a disinfectant. 

19. Show the disinfecting value of heat. 

20. Of fresh air and light. 

21. Name the common disinfectants recommended by the 
National Board of Health for general use. 

22. Give the principal instructions of this Board on " How to 
use disinfectants." 



POISONS AND THEIR ANTIDOTES. 375 



CHAPTER 39. 

POISONS AND THEIR ANTIDOTES. 

A Poison may be defined as any substance capable 
of producing within the animal or human body a 
noxious or deadly effect. This definition includes, of 
course, injurious chemical compounds of an inorganic 
nature, also certain vegetable products, and the venom 
of animals. Many poisonous matters produce local 
effects of irritation and pain, such as the strong acids 
and alkalies and corrosive mineral compounds ; others 
act remotely upon the body, that is, through absorp- 
tion by the blood and consequent derangements of the 
nervous system ; such are called narcotic or neurotic 
poisons, and include opium, aconite, alcohol, etc. All 
poisons in large quantities operate speedily when 
taken into the body ; though some are cumulative in 
their nature, that is, they may be taken in repeated 
doses each too small to produce alone serious effects, 
but by accumulating within the body they give rise to 
chronic derangements of increasing severity : of such 
poisons lead and arsenic are examples. 

General Treatment in Poisoning" Cases: — in 

most severe cases of poisoning, the symptoms will be 
clearly marked, and the attendant circumstances will 
likely indicate the nature of the poisonous substance 
used. Prompt measures for relief should be taken. 
As a rule, when it is found that a poison has been 
swallowed, the first thing to be done is to remove the 



376 DOMESTIC SCIENCE. 

contents of the stomach, thus preventing farther 
absorption of the poison. If vomiting has not 
occurred, simple emetics should be administered. 
Among common emetics, the wine of ipecacuanha is 
good ; give at least a tablespoonful in the case of an 
adult, less for children. In the absence of this, mix 
powdered mustard and salt in water — a teaspoonful 
of mustard and an equal amount of salt, the latter 
dissolved and the former well mixed in a pint of warm 
water. A tablespoonful of powdered alum, with an 
equal quantity of molasses, honey, or sugar, well 
stirred in water, is a good emetic dose. Mechanical 
irritation in the throat, as by tickling with a feather or 
the finger, will often induce vomiting. As quickness 
of action is of great import, repeat the emetic doses 
at frequent intervals (every ten or fifteen minutes) till 
copious vomiting occurs; then aid the operation by 
plentiful draughts of dilutent liquids, such as warm 
water, alone or with sugar; mucilage of gum-arabic 
(do not use the prepared gum mucilage, it contains 
poisonous ingredients), watery infusions of slippery 
elm, or flax-seed tea. A stomach pump, if at hand, 
may be used to good effect in cleansing the stomach. 
AntidoteS.^ — Another important step is to neutral- 
ize and thus render inert, as far as possible, the poison 
within the body ; for this purpose certain antidotes 
should be given. The object of the antidote is to 
produce insoluble compounds which will be secure 
against absorption till they can be removed from the 
body. Below are named some of the commonest 
poisons and the antidotes well suited to each case. 



POISONS AND THEIR ANTIDOTES. 377 

Common Poisons and their Antidotes. 

Strong Minei^al Acids, such as nitric acid (aqua- 
fortis), hydrochloric acid (muriatic), sulphuric acid 
(oil of vitriol). Administer alkalies, such as soda, 
lime, whiting, magnesia, stirred in water. In the 
absence of these, take some plaster from the wall, 
crush fine, stir in milk, and administer ; soap dissolved 
in water is good. In any case, follow with dilutents. 

Organic Acids: — Oxalic acid is frequently taken by 
mistake, because of its resemblance to another house- 
hold chemical — Epsom salts. Antidotes for oxalic 
acid — magnesia, chalk, or even wall plaster mixed 
with water. Prussic acid may be taken as oil of bitter 
almonds, or potassium cyanide ; the effect is usually 
too rapid to admit of effectual antidotes, when possi- 
ble,- however, give very dilute ammonia, or chlorine 
water, or let the dilute gases from such be inhaled. 
Cold water applied to the spine is beneficial. 

Strong Alkalies, such as ammonia, potash — as 
caustic potash, potash lye, pearlash, potassium nitrate 
(saltpeter) ; soda, as soda lye, etc. Give freely dilute 
acids, such as vinegar, citric acid, or tartaric acid, in 
water ; these tend to neutralize the alkali. Give also 
large doses of oil, as olive oil, linseed oil, or castor 
oil ; the oils form soap with strong alkalies, and so 
delay their ill effects. 

Antimony compounds, as tartar emetic, wine of 
antimony, etc. Vomiting is of great importance. 
Give astringent infusions, as strong green tea; let tea 



3 78 DOMESTIC SCIENCE. 

leaves be chewed and swallowed ; infusion of oak- 
bark, nut galls, or tannin. 

Arsenic : — Usually taken as white arsenic, Paris 
green, Scheele's ^reen, cobalt powders; and among 
patented preparations: Fowler's solution, and various 
mouse and rat poisons. Give abundance of milk and 
white of eggs. The best antidote is the hydrated per- 
oxide of iron ; to prepare which : pour together 
solutions of perchloride of iron and dilute ammonia, 
both of which may be obtained at drug stores ; a 
brown precipitate forms in the mixture ; strain through 
linen ; mix the brown mass with water and administer 
freely. 

Copper Salts: as copper acetate (verdigris) often 
imbibed from unclean copper vessels used in cooking 
or pickling; copper sulphate (blue vitriol). Give 
freely of milk, white of eggs, and carbonate of soda. 

Iron: as iron sulphate (green vitriol). Give car- 
bonate of soda and plenty of mucilaginous drinks. 

Lead: as lead acetate (sugar of lead), lead carbon- 
ate (white lead), red lead, also from water that has 
been kept in leaden pipes or vessels. Give very dilute 
sulphuric acid, or Epsom salts, in water. Administer 
oil and mucilaginous drinks with emetics. In chronic 
cases of lead poisoning, as in " leading" from expos- 
ure to fumes of the metal, repeated doses of highly 
diluted sulphuric acid, or of potassium iodide, may be 
recommended. 

Mercury: as mercuric chloride (corrosive sublim- 
ate), ammoniated mercury (white precipitate), mer- 
curic oxide (red precipitate), mercuric sulphide (ver- 



POISONS AND THEIR ANTIDOTES, 379 

milion.) Give white of egg in abundance, or flour 
mixed with water or milk, or soap and water. Avoid 
strong emetics or irritating substances. Use the stom- 
ach pump if possible. 

Silver: as silver nitrate (lunar caustic). Give salt 
and water, then oil. 

Zi7ic : as zinc chloride (butter of zinc), zinc sul- 
phate (white vitriol). Zinc salts are themselves 
emetics ; relieve the vomiting by dilutent drinks, and 
give sodium carbonate in water. 

Phosphorus, from matches and vermin poisons. 
Give magnesia, or chalk, in water ; flour in water ; 
follow with mucilaginous liquids in abundance. 

Certain Gases are sometimes breathed with toxic 
effect. For chlorine inhalation, let the sufferer cauti- 
ously breathe ammonia. In cases of poisoning from 
carbon dioxide, carbon monoxide (from fumes of coke 
or of burning charcoal), hydrogen sulphide, illuminat- 
ing gas ; relieve the stupor by applying cold water to 
the head, — give stimulants, and establish artificial res- 
piration. To effect this, take the patient into the fresh 
air, and, except in the severest weather, expose the 
face, neck, and chest ; clear the throat of mucus by 
turning the patient face downward with mouth open ; 
hold dilute ammonia to the nostrils. If respiration 
does not take place, put the patient face downward, 
then roll the body almost over and back again, regu- 
larly (about fifteen times a minute) ; this causes alter- 
nate compression and expansion of the chest and 
favors the influx and escape of air. Rub the limbs 
upward, using considerable energy. 



380 DOMESTIC SCIENCE. 

Narcotic poisons: — as opium (gum opium, lauda- 
num, paregoric, infusion of poppies, soothing syrup ; 
cholera mixtures ; most patented "cordials"), digi- 
talis, aconite, hemlock, belladonna ; stramonium. 
Give emetics, or use stomach pump promptly. Keep 
the patient awake, in motion if possible ; dash cold 
water on head and shoulders, administer strong coffee 
or tea; also vinegar or lemon juice. Keep the limbs 
warm ; if necessary resort to artificial respiration. As 
consciousness returns, continue the use of coffee and 
give weak stimulants, such as wine or brandy in water. 
Strychnine and brucine (nux vomica) are somewhat 
allied to the foregoing, though these usually produce 
violent spasms. Cautiously administer chloroform or 
ether to quiet the spasms ; then give powdered char- 
coal in water (>yalker). 

Irritant vegetable poisons, such as croton oil, and 
many essential oils and essences, are often swallowed 
with poisonous effect. Vomiting is likely to occur 
spontaneously ; if not, however, administer emetics 
without delay, aid vomiting by warm draughts, and 
follow with an efficient purgative. Give vinegar, 
lemon juice, or strong coffee. 

Poisonous meats, fish, or cheese are sometimes eaten. 
Evacuate the stomach without delay by emetics and 
purgatives, and give good doses of vinegar and water. 
Hutchinson recommends that this treatment be followed 
by small doses of ether with a few drops of laudanum 
in sweetened water. 

Animal venom may be received from bites of mad 
dogs, and of snakes, and spiders, and the stings of 



POISONS AND THEIR ANTIDOTES. 381 

insects. Wash the wound with dilute ammonia ; if on 
a limb, tie a bandage above the place of injury ; if pos- 
sible let the wound be freely sucked, the mouth being 
afterward well rinsed with water. Moderate amounts 
of alcoholic stimulants may be given. In severe cases 
ammonia may be injected into the veins, — only a com- 
petent physician or surgeon should attempt this 
operation. As an extreme measure, the wound may 
be cauterized by the application of nitrate of silver, or 
by pressing the heated point of a small poker, or a 
knitting needle, into the wound. In the case of 
insect stings, extract the sting if still in the wound : a 
pair of forceps will aid in this, or the barrel of a small 
key may be pressed around the sting. Apply to the 
wound a little dilute ammonia, or spirits of camphor, 
or moistened soda; or in lack of these, alkaline mud, 
or earth mixed into a mud with saliva. A cloth 
dipped in a weak aqueous solution of carbolic acid may 
be applied to the affected part. If symptoms of inter- 
nal distress make their appearance, give cautiously 
four or five drops of carbolic acid in a wine glass of 
water. 

These are but a few of the commonest poisons ; the 
antidotes recommended are such as are likely to be of 
ready access. 



REVIEW. 

1. What is poison? 

2. What methods of general treatment would you follow in 
cases of poisoning? 

3. What is a chemical antidote for a poison. 



382 DOMESTIC SCIENCE. 

4. Name the antidotes and general treatment you would em- 
ploy in cases of poisoning from the following substances; as far 
as possible explaining the action of the antidote in each case: 

5. Sulphuric acid. 

6. Oxalic acid. 

7. Prussic acid. 

8. Ammonia. 

9. Potash. 

10. Soda. 

11. Tartar emetic. 

12. Arsenical compounds. 

13. Copper salts. 

14. Iron salts. 

15. Lead compounds. 

16. Mercury compounds. 

17. Silver nitrate. 

18. Zinc compounds. 

19. Phosphorus. 

20. How would you treat a case of poisoning from coal gas? 

21. Name the chief narcotic poisons. 

22. How would you treat a case of opium poisoning? 

23. Of strychnine poisoning? 

24. How would you treat a case of snake-bite? 

25. Of stinging by insects? 



INDEX. 



Absorbents of Gases 365 

Acid, Acetic 280 

" Boric, as antiseptic, 346 
" Citric 278 

" Malic 279 

" Oxalic 279 

" Salicylic, as preser- 
vative 347 
" Tartaric 279 
Acids, Vegetable 278 
Aerated Bread 313 
Aeration of Blood 73 
Air, Composition of 38 
'* Contamination of 60, 65, 69 
" Elasticity of 15 
" Humidity of 48 
" Impenetrability of 12 
" Proof of Existence 11 
" Physical Properties 

of 11 

" Permanency of 51 

" Pressure of 16, 24, 25 

Air Pump 19 

Air Purified by Plants 52 

Air of Rooms 60 

Air Supply for Dwellings 66 

" Vitiated, Effect on 

Health 74, 77 

" Weight of 14 

Albuminoids in Foods 286, 293 
Albumen 286 

Alum for Purifying Water 232 
Alum Waters 238 

Alcohol, as Antiseptic 345 

Alkalies, as Cleansing 

Agents 351 

Ammonia in Water 212 



Ammonia, as Cleansing 

Agent 356 
Amyloid Foods 269, 280 
Analysis and Synthesis 246 
Aneroid Barometer 29 
Animals and Plants, mu- 
tually dependent 57 
Anthracite 138 
Antidotes to Poisons 376 
Antiseptics — in Food Pre- 
servation 344 
Arsenical Pigments 90 
Artesian Wells 188 
Bacteria 340 
Baking of Dough 310 
Baking Powders 312 
Barometers 27 
Barometer — Aneroid 29 
" Siphon 27 
" Wheel 28 
" as a Weather 

Indicator 30 
Barley as Food 313 
Beef- tea 320 
Beets 299 
Bituminous Coal 137 
Bleaching 358 
Bleaching by Chlorine 359 
" " Sulphur- 
Dioxide 361 
" Powder 361 
Blood, Clotting of 288 
" Aeration of 73 
Blowpipe, Mouth 156 
Boiling of Water 226 
"Boiling" in Cookery 298 
Boric Acid, Preservative 346 



384 



INDEX. 



Bottling and Canning 342 

Bran, of Grains 306 

Bread, Aerated 313 

Bread, New and Stale 311 

Broiling of Meat 321 

Buckwheat as Food 315 
Burners, Gas 164, 165 

Butter 327 

Butters— Artificial 327 

Cabbage 301 

Candle Flame 133 

Canning and Bottling 342 

Cannel Coal 136 

Carbon-Dioxide— Proper- 
ties of 44 
" " Tests for 47 

" " Exhaled 

by Human 
Beings 64 
" " Absorbed 

by Plants 54 
Carbonaceous Foods 269, 278 
Carboniferous Age 56 

Carbolic Acid, Disinfectant 368 
Carrots 299 

Casein 291 

Carbonated Mineral 

Waters 236 

Calcium Waters 237 

Cellars Under Houses 68 

Celsius Thermometer Scale 115 
Chalybeate Waters 237 

Charcoal, as Absorbent 365 
" as Fuel 139 

Cheese 328 

Chloride of Lime, Disinfec- 
tant 367 
Chlorine, Bleaching Agent 359 
" Disinfectant 366 
*' in Water 214 



Chlorophyle 54 

Citric Acid 278 

Cleansing Agents 351 

Coal, Varieties of 135 

Coal Gas, as Fuel 139 

" "as Illuminant 164 
Coal Miners, Mortality 

Among 82 

Cocoa and Chocolate 337 

Coffee 336 

Coke 139 
Combustion, Means of Air 

Vitiation 69 

Compensation Pendulums 111 

Condenser, Liebig's 229 

Condiments 331 

Conduction of Heat 120 
Consumption, from Foul 

A.ir 74 
Convection of Heat 122 
Cookery, Purposes of 259 
Copperas, Disinfectant 369 
Corrosive Sublimate, Disin- 
fectant 370 
Cream 327 
Creosote, Antiseptic 346 
Currents, Ventilating 101 

Dead Sea, Water of 201, 240 

Decay of Organic Matter 340 

Dextrin 276 

Dial -face Thermometer 117 

Diffusion of Gases 39 
Digestibility of Foods 256, 258 

Disinfectants and Deodor- 
izers 364 

Disinfection, Instructions 

for 371 

Distillation of Water 227 

Double- case Stove 147 



INDEX. 



385 



Dough 309 

Dropping Tube 35 

Drying, as Preservative 344 

Drying Power of Air 48 

Dust in Air 81 
Dust, Constituents of 85, 86 

" Household 87 
Dust-inhaling Occupations 81 

Dust, Hard and Irritating 82 

" Poisonous 84 

Dust- traps in Houses 88 
Dysentery, from Impure Air 76 
Dysentery, from Impure 

Water 216 

Efflorescence of Minerals 174 

Eggs as Food 323 

" Preservation of 347 

Electric Lights 166 

Electrolysis of Water 243 
Emetics in Poisoning Cases 376 
Esquimaux, Ventilation 

among 76 
Exhaust Fan in Ventilat- 
ing 101 
Expansion by Heat 108 

Fahrenheit Thermometer 113 
Fan in Ventilating 101 
Fats and Oils 281 
Fats in Food 281 
Fats in Animals 283 
Fats in Plants 282 
Fibers of Meat 288 
Fibrin 288 
Filtration of Water 230 
Filter, Pasteur- Chamber- 
land 231 
Fireplace, Open 145 
" Primitive 143 
Fire Fly's Light 168 



Fire-test Point of Oils 162 

Fish as Food 318 

Flame, Luminosity of 155 

" Structure of 131 

Flashing Point of Oils 162 

Flesh as Food 317 

Flour as Food 306 

Food, Bodily Need of 253 

Foods, Auxiliary 331 

" Carbonaceous 269 

" Classification of 254 

" Mineral 261, 267 

" Mixed 255 

*' Nature of 253 

" Nitrogenous 286 

" Preservation of 340 

Force Pump 34 

Freezing of Water 183 

" as Preservative 341 

Frying 321 

Frying-kettle 322 

Fruits, as Food 302 

Fuels 134 

Fungi 55 

Gaseous Fuel 139, 164 

Gases, Diffusion of 39 
Gases, Dissolved in Water 

208, 210 

Gasoline as Fuel 140 

Gelatin 289 

Gillis Ventilating System 101 

Glucose 275 

Gluten 293 

Goitre and Hard Water 204 

Grains as Food 305 
Green Vitriol, Disinfectant 369 

Grilling of Meat 321 

Gums in Food 275 



Hardness of Water 



201 



386 



INDEX. 



Heat, Agent in Disinfecting 370 

Heat, Conduction of 120 

" Convection of 122 
" Expansion by 108, 112 

" Latent 124 

" Radiation of 123 

*' Properties of 107 

" Specific 125 
Hermetic Sealing, as 

preservative 342 

House Warming 143 

Human Respiration 71 

Humidity of Air 48 

Hydrogen 245 

Ice Crystals 184 

Ice, Uses of 181 

Iceland, Ventilation in 76 

Illuminants, Fluid 162 

" Gaseous 164 

" Electric Light 166 

Illumination, Waste in 167 
Indian Corn as Food 314 

Iron in Food 266 

Iron Sulphate, Disinfectant 369 



Jelly, Pectin 



280 



Kerosene 



162 

Lamp 157 

Danger from 163 



157 



Lamp, Simple 

" Argand, or Stu- 
dent's 157 
" Hollow-wick 159 
Latent Heat 124 
Lead Chloride, Disinfect- 
ant 370 
Leaves as Food 301 
Lemon Juice 332 



Liebig Condenser 229 
Lifting Pump 32 
Light, Agent in Disinfect- 
ing 370 
" Natural and Artifi- 
cial 154 
Lighting, Artificial 157 
Lignite 136 
Lime in Food 265 
" in Disinfectants 365 
Lyman's Ventilator 96 

Magdeburg Hemispheres 21 
Maize as Food 314 
Malic Acid 279 
Marine Soap 354 
Matches 140 
Meats, Cookery of 318 
Mechanical Ventilators 101 
Mercuric Chloride, Disin- 
fectant 370 
Milk as Food 325 
Mines, Ventilation of 96 
Mineral in Foods 1, 267 
Minerals, Water in 173 
Mineral Waters 236, 241 

Narcotic Poisons 380 

Nitrogen in Air 40 

" Properties of 42 

Nitrogenous Foods 286 

" Impurities in 

Water 212 

Oats as Food 315 

Oils, Fixed and Essential 281 

" Essential 332 

" and Fats 281 

" in Plants 282 

" in Animals 283 

Oil, as preservatjv 345 



INDEX. 



387 



Olein 283 

Onions as Food 298 

Open Fireplace 145 
Organic Impurities in 

Water 212, 216, 225 

Oxalic Acid 279 

Oxygen in the Air 41 

" Preparation of 42 

*' Properties of 43 

" Supplied by Plants 52 

Oxy- hydrogen Flame 247 

Palmitin 283 

Parsnips 299 
Pasteur- Chamberland 

Filter 231 
Pectin 280 
Pendulum, Compensation 111 
Penicillium, a Mold 267 
Phosphorus in Foods 267 
Pickles 332 
Pipette 35 
Plants, Water in 175 
Plants, Air Purifiers 54 
" and Animals mutu- 
ally dependent 57 
Poisonous Dust 84 
" Meat, Fish, etc. 380 
'• Wall-paper 89 
Poisons and Antidotes 375 
Poison, Acids 377 
" Alkalies 377 
" Antimony 377 
" Arsenic 378 
" Animal 380 
" Copper 378 
" Gases 379 
" Iron 378 
" Lead 378 
" Mercury 378 
" Phosphorus 379 



Poison, Silver 


379 


" Strychnine 


380 


" Zinc 


379 


Poisons, Vegetable 


380 


Poisons, Narcotic 


380 


Potatoes as Food 


295 


" Cookery of 


297 


Proteids in Food 


286 


Pump, Air 


19 


" Force 


34 


" Lifting 


32 


Radiator- steam 


151 


Radiation of Heat 


123 


Radishes as Food 


300 


Rain Water 


187 


Registers, Ventilating 


100 


Respiration, Organs and 




Process 


71 


Respiration, Vitiating 




Effect 


64 


Rice as Food 


315 


River Water 


194 


Roasting of Meat 


320 


Rye as Food 


813 


Salads 


301 


Saline Waters 


239 


Salt in Food 


262 


" Bodily Need of 


263 



" in Human Body 262 

" as Antiseptic 344 

Salt Lake, Water of 201, 239 
Salt Lake City, Air Pres- 
sure at 26 
Salicylic Acid, Antiseptic 347 
Saponification 353 
Scheele's Green on Wall- 

Paper • 90 

Schweinfurth, Green 91 

Scrofula,from Impure Air 74 
Seeds for Food 303 



388 



INDEX. 



Seething of Meat 318 

Semi -Bituminous Coal 137 

Siplion 35 

Siphon-Barometer 27 

Smell, Sense of 62 

Soaps 352 

" Hard and Soft 353 

Soap, Impure 355 

" Marine 354 

" and Hard Water 202 

Soda Water 209 

Solutions, Aqueous 197 

Solids Dissolved in Water 197 

Sore Throat from Impure 

Air 75 

Soup Making 319 

Specific Heat 125 

Spices, as Condiments 333 

Springs, Kinds of 188 

Starch in Foods 269 

" " Plants 271 

Stearine 283 

Steam Warming 150 

Steam, Uses of 182 

Storm Glass 31 

Stoves 146 

Student's Lamp 157 

Sugar in Food 273 

Sugar, Saccharose 273 

" Glucose 275 

" as antiseptic 345 

Sulphur in Foods 267 

" Dioxide,Disinfect- 

ant 367 
Sulphur Dioxide in Bleach- 
ing 361 
Sulphur Waters 236 
Syringe, Operation of 31 
Synthesis and Analysis 246 
Tabernacle Roof, Salt Lake 26 
Tannin, for Water 233 



Tartaric Acid 279 

Tea 334 

Temperature of Rooms 143 
Thermometers 112 

Thermometer, Celsius 115 

*' Dial -face 117 

" Fahrenheit 113 

Thymol, Disinfectant 369 

Tinder-box, 140 

Tin Miners, Mortality of 82 
Tonsilitis, from Impure Air 75 
Tuberculosis, from Impure 

Air 74 

Turnips 299 

Uses of Water 181 

Vapor of Water in Air 47 

Vapor Gas 165 

Vegetable Acids 278 

" Jelly 280 

" Gums 275 

" ' Foods 295, 305 

Ventilation 93 

Ventilating Currents 95, 98, 102 
Ventilation, Gillis system 101 
" by Heat 99,101 

" Mechanical 101 

" in Mines 96 

Ventilator, Lyman's 96 

Ventilator-burner 165 

Vinegar 331 

" as antiseptic 345 

Vitriol, Green, Disinfect- 
ant 369 
" White,Disinfectant 370 

Wall Paper, Poisonous 89 

Warm Air, for House 

Warming 150 

** Water, for House 

Warming 152 

Washing Compounds 355 



INDEX. 



389 



Water, Analysis and Synthe- 
sis 246 
Water-bath 319 
Water, Boiling of 226 
" Chemical Purifica- 
tion 232 
" Cleansing Agent 351 
" of Crystallization 174 
" Distillation of 227 
" Electrolysis of 243 
" Filtration of 230 
" Freezing of 183 
" Hardness in 201, 204 
" in Animals 178 
" in Human Tissues 179 
" in Minerals 173 
" in Plants 175 
" Occurrence in 

Bodies 173 

" Organisms in 219 

" Organic Impurities 

212, 216, 225 
'' Solid Impurities 199 
'' Natural Purifica- 
tion of 194 
*' Purification of 226 
" Purity Tests 221 
" Rain 187 
" River 194 
" Spring 193 
" Softening of 233 



Water, Solvent for Solids 197 
" " " Gases 

206, 210 
" Sources of 187 

» Uses of 181 

-' of Wells 195, 218 

Waters, Mineral 236, 241 

'' Alum 238 

" Calcium 237 

" Carbonated 236 

" Chalybeate 237 

" Saline 239 

" Siliceous 238 

" Sulphur 236 

" Dead Sea 201,240 

' ' Great Salt Lake 201, 239 
Water-gas 164 

Watery Vapor in Air 48 

Wheat as Food 305 

Wheel Barometer 28 

Window Currents 103, 105 

Wood, as Fuel 135 

Yeast in Bread Making 310 
" Compressed 309 

" Structure and Pro- 

ties 307 

Zinc Chloride 370 

Zinc Salts, Disinfectants 370 
Zinc Sulphate 370 



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